Configuring the forward and return methods and adding authentication

The WCCP forwarding method determines how intercepted traffic is transmitted from the WCCP router to the WCCP cache engine. There are two different forwarding methods:

• GRE forwarding (the default) encapsulates the intercepted packet in an IP GRE header with a source IP address of the WCCP router and a destination IP address of the target WCCP cache engine. The results is a tunnel that allows the WCCP router to be multiple hops away from the WCCP cache server.
• L2 forwarding rewrites the destination MAC address of the intercepted packet to match the MAC address of the target WCCP cache engine. L2 forwarding requires that the WCCP router is Layer 2 adjacent to the WCCP client.

You can use the following command on a FortiGate unit configured as a WCCP router to change the forward and return methods to L2:

config system wccp edit 1 set forward-method L2 set return-method L2

end

You can also set the forward and return methods to any in order to match the cache server configuration.

By default the WCCP communication between the router and cache servers is unencrypted. If you are concerned about attackers sniffing the information in the WCCP stream you can use the following command to enable hashbased authentication of the WCCP traffic. You must enable authentication on the router and the cache engines and all must have the same password.

config system wccp edit 1 set authentication enable set password <password>

end

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WCCP packet flow

The following packet flow sequence assumes you have configured a FortiGate unit to be a WCCP server and one or more FortiGate units to be WCCP clients.

1. A user’s web browser sends a request for web content.
2. The FortiGate unit configured as a WCCP server includes a security policy that intercepts the request and forwards it to a WCCP client.

The security policy can apply UTM features to traffic accepted by the policy.

3. The WCCP client receives the WCCP session.
4. The client either returns requested content to the WCCP server if it is already cached, or connects to the destination web server, receives and caches the content and then returns it to the WCCP server.
5. The WCCP server returns the requested content to the user’s web browser.
6. The WCCP router returns the request to the client web browser.

The client we browser is not aware that all this is taking place and does not have to be configured to use a web proxy.

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Example caching HTTP sessions on port 80 and HTTPS sessions on port 443 using WCCP

This example configuration is the same as that described in Example caching HTTP sessions on port 80 and

HTTPS sessions on port 443 using WCCP on page 295 except that WCCP now also cached HTTPS traffic on port 443. To cache HTTP and HTTPS traffic the WCCP service group must have a service ID in the range 51 to 255 and you must specify port 80 and 443 and protocol 6 in the service group configuration of the WCCP client.

Also the security policy on the WCCP_srv that accepts sessions from the internal network to be cached must accept HTTP and HTTPS sessions.

 

Example caching HTTP sessions on port 80 and HTTPS sessions on port 443 using WCCP

Configuring the WCCP server (WCCP_srv)

Use the following steps to configure WCCP_srv as the WCCP server for the example network. The example steps only describe the WCCP-related configuration.

To configure WCCP_srv as a WCCP server

1. Add a port2 to port1 security policy that accepts HTTP traffic on port 80 and HTTPS traffic on port 443 and is configured for WCCP:

config firewall policy edit 0 set srtintf port2 set dstintf port1 set srcaddr all set dstaddr all set action accept set schedule always set service HTTP HTTPS set wccp enable set nat enable

end

2. Add another port2 to port1 security policy to allow all other traffic to connect to the Internet.

config firewall policy edit 0 set srtintf port2 set dstintf port1 set srcaddr all set dstaddr all set action accept set schedule always set service ANY

set nat enable

end

3. Move this policy below the WCCP policy in the port2 to port1 policy list.
4. Enable WCCP on the port5 interface.

config system interface edit port5 set wccp enable

end

5. Add a WCCP service group with service ID 90 (can be any number between 51 and 255).

config system wccp edit 90 set router-id 10.51.101.100 set server-list 10.51.101.0 255.255.255.0

end

6. Add a firewall address and security policy to allow the WCCP_client to connect to the internet.

config firewall address edit WCCP_client_addr set subnet 10.51.101.10

Example caching HTTP sessions on port 80 and HTTPS sessions on port 443

end

config firewall policy edit 0 set srtintf port5 set dstintf port1 set srcaddr WCCP_client_addr

set dstaddr all set action accept set schedule always set service ANY set nat enable end

Configuring the WCCP client (WCCP_client)

Use the following steps to configure WCCP_client as the WCCP client for the example network. The example steps only describe the WCCP-related configuration.

To configure WCCP_client as a WCCP client

1. Configure WCCP_client to operate as a WCCP client. config system settings set wccp-cache-engine enable

end

You cannot enter the wccp-cache-engine enable command if you have already added a WCCP service group. When you enter this command an interface named w.<vdom_name> is added to the FortiGate configuration (for example w.root). All traffic redirected from a WCCP router is considered to be received at this interface of the FortiGate unit operating as a WCCP client. A default route to this interface with lowest priority is added.

2. Enable WCCP on the port1 interface.

config system interface edit port1 set wccp enable

end

3. Add a WCCP service group with service ID 90. This service group also specifies to cache sessions on ports 80 and 443 (for HTTP and HTTPS) and protocol number 6.

config system wccp edit 90 set cache-id 10.51.101.10 set router-list 10.51.101.100

ports 80 443 set protocol 6 end

packet flow

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Example caching HTTP sessions on port 80 using WCCP

In this example configuration (shown below), a FortiGate unit with host name WCCP_srv is operating as an Internet firewall for a private network is also configured as a WCCP server. The port1 interface of WCCP_srv is connected to the Internet and the port2 interface is connected to the internal network.

All HTTP traffic on port 80 that is received at the port2 interface of WCCP_srv is accepted by a port2 to port1 security policy with WCCP enabled. All other traffic received at the port2 interface is allowed to connect to the Internet by adding a general port2 to port1 security policy below the HTTP on port 80 security policy.

A WCCP service group is added to WCCP_srv with a service ID of 0 for caching HTTP traffic on port 80. The port5 interface of WCCP_srv is configured for WCCP communication.

A second FortiGate unit with host name WCCP_client is operating as a WCCP client. The port1 interface of WCCP_client is connected to port5 of WCCP_srv and is configured for WCCP communication.

WCCP_client is configured to cache HTTP traffic because it also has a WCCP service group with a service ID of

0.

WCCP_client connects to the Internet through WCCP_srv. To allow this, a port5 to port1 security policy is added to WCCP_srv.

FortiGate WCCP server and client configuration

Configuring the WCCP server (WCCP_srv)

Use the following steps to configure WCCP_srv as the WCCP server for the example network. The example steps only describe the WCCP-related configuration.

Example caching HTTP sessions on port 80 using WCCP

To configure WCCP_srv as a WCCP server

1. Add a port2 to port1 security policy that accepts HTTP traffic on port 80 and is configured for WCCP:

config firewall policy edit 0 set srtintf port2 set dstintf port1 set srcaddr all set dstaddr all set action accept set schedule always set service HTTP set wccp enable set nat enable

end

2. Add another port2 to port1 security policy to allow all other traffic to connect to the Internet.

config firewall policy edit 0 set srtintf port2 set dstintf port1 set srcaddr all set dstaddr all set action accept set schedule always set service ANY set nat enable

end

3. Move this policy below the WCCP policy in the port2 to port1 policy list.
4. Enable WCCP on the port5 interface.

config system interface edit port5

set wccp enable

end

5. Add a WCCP service group with service ID 0.

config system wccp

edit 0 set router-id 10.51.101.100 set server-list 10.51.101.0 255.255.255.0

end

6. Add a firewall address and security policy to allow the WCCP_client to connect to the internet.

config firewall address edit WCCP_client_addr set subnet 10.51.101.10

end

config firewall policy edit 0 set srtintf port5 set dstintf port1 set srcaddr WCCP_client_addr

set dstaddr all set action accept

Example caching HTTP sessions on port 80 and HTTPS sessions on port 443

set schedule always set service ANY set nat enable end

Configuring the WCCP client (WCCP_client)

Use the following steps to configure WCCP_client as the WCCP client for the example network. The example steps only describe the WCCP-related configuration.

To configure WCCP_client as a WCCP client

1. Configure WCCP_client to operate as a WCCP client.

config system settings set wccp-cache-engine enable

end

You cannot enter the wccp-cache-engine enable command if you have already added a WCCP service group. When you enter this command an interface named w.<vdom_name> is added to the FortiGate configuration (for example w.root). All traffic redirected from a WCCP router is considered to be received at this interface of the FortiGate unit operating as a WCCP client. A default route to this interface with lowest priority is added.

2. Enable WCCP on the port1 interface.

config system interface edit port1 set wccp enable

end

3. Add a WCCP service group with service ID 0.

config system wccp edit 0 set cache-id 10.51.101.10 set router-list 10.51.101.100

end

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WCCP Configuration

WCCP configuration overview

To configure WCCP you must create a service group that includes WCCP servers and clients. WCCP servers intercept sessions to be cached (for example, sessions from users browsing the web from a private network). To intercept sessions to be cached the WCCP server must include a security policy that accepts sessions to be cached and WCCP must be enabled in this security policy.

The server must have an interface configured for WCCP communication with WCCP clients. That interface sends and receives encapsulated GRE traffic to and from WCCP clients. The server must also include a WCCP service group that includes a service ID and the addresses of the WCCP clients as well as other WCCP configuration options.

To use a FortiGate unit as a WCCP client, the FortiGate unit must be set to be a WCCP client (or cache engine). You must also configure an interface on the client for WCCP communication. The client sends and receives encapsulated GRE traffic to and from the WCCP server using this interface.

The client must also include a WCCP service group with a service ID that matches a service ID on the server. The client service group also includes the IP address of the servers in the service group and specifies the port numbers and protocol number of the sessions that will be cached on the client.

When the client receives sessions from the server on its WCCP interface, it either returns cached content over the WCCP interface or connects to the destination web servers using the appropriate interface depending on the client routing configuration. Content received from web servers is then cached by the client and returned to the WCCP server over the WCCP link. The server then returns the received content to the initial requesting user web browser.

Finally you may also need to configure routing on the server and client FortiGate units and additional security policies may have to be added to the server to accept sessions not cached by WCCP.

WCCP service groups, service numbers, service IDs and well known services

A FortiGate unit configured as a WCCP server or client can include multiple server or client configurations. Each of these configurations is called a WCCP service group. A service group consists of one or more WCCP servers (or routers) and one or more WCCP clients working together to cache a specific type of traffic. The service group configuration includes information about the type of traffic to be cached, the addresses of the WCCP clients and servers and other information about the service.

A service group is identified with a numeric WCCP service ID (or service number) in the range 0 to 255. All of the servers and clients in the same WCCP service group must have service group configurations with the same WCCP service ID.

The value of the service ID provides some information about the type of traffic to be cached by the service group. Service IDs in the range 0 to 50 are reserved for well known services. A well known service is any service that is defined by the WCCP standard as being well known. Since the service is well known, just the service ID is required to identify the traffic to be cached.

service groups, service numbers, service IDs and well known services

Even though the well known service ID range is 0 to 50, at this time only one well known service has been defined. Its service ID 0, which is used for caching HTTP (web) traffic.

So to configure WCCP to cache HTTP sessions you can add a service group to the WCCP router and WCCP clients with a service ID of 0. No other information about the type of traffic to cache needs to be added to the service group.

Since service IDs 1 to 50 are reserved for well know services and since these services are not defined yet, you should not add service groups with IDs in the range 1 to 50.

FortiOS does allow you to add service groups with IDs between 1 and 50. Since these service groups have not been assigned well known services, however, they will not cache any sessions. Service groups with IDs 51 to 255 allow you to set the port numbers and protocol number of the traffic to be cached. So you can use service groups with IDs 51 to 255 to cache different kinds of traffic based on port numbers and protocol number of the traffic. Service groups 1 to 50; however, do not allow you to set port numbers or protocol numbers so cannot be used to cache any traffic.

To cache traffic other than HTTP traffic you must add service groups with IDs in the range 51 to 255. These service group configurations must include the port numbers and protocol number of the traffic to be cached. It is the port and protocol number configuration in the service group that determines what traffic will be cached by WCCP.

Example WCCP server and client configuration for caching HTTP sessions (service ID = 0)

Enter the following command to add a WCCP service group to a WCCP server that caches HTTP sessions. The IP address of the server is 10.31.101.100 and the WCCP clients are on the 10.31.101.0 subnet. The service ID of this service group is 0.

config system wccp edit 0 set router-id 10.31.101.100

set server-list 10.31.101.0 255.255.255.0

end

Enter the following commands to configure a FortiGate unit to operate as a WCCP client and add a service group that configures the client to cache HTTP sessions. The IP address of the server is 10.31.101.100 and IP address of this WCCP clients is 10.31.101.1 subnet. The service ID of this service group is 0.

config system settings set wccp-cache-engine enable

end

config system wccp edit 0 set cache-id 10.31.101.1 set router-list 10.31.101.100 end

WCCP service groups, service numbers, service IDs and well known services

You cannot enter the wccp-cache-engine enable command if you have already added a WCCP service group. When you enter this command an interface named w.<vdom_name> is added to the FortiGate configuration (for example w.root). All traffic redirected from a WCCP router is considered to be received at this interface of the FortiGate unit operating as a WCCP client. A default route to this interface with lowest priority is added.

Example WCCP server and client configuration for caching HTTPS sessions

Enter the following command to add a service group to a WCCP server that caches HTTPS content on port 443 and protocol 6. The IP address of the server is 10.31.101.100 and the WCCP clients are on the 10.31.101.0 subnet. The service ID of this service group is 80.

config system settings set wccp-cache-engine enable

end

config system wccp edit 80 set router-id 10.31.101.100

set server-list 10.31.101.0 255.255.255.0

set ports 443 set protocol 6

end

Enter the following commands to configure a FortiGate unit to operate as a WCCP client and add a service group that configures client to cache HTTPS sessions on port 443 and protocol 6. The IP address of the server is 10.31.101.100 and IP address of this WCCP clients is 10.31.101.1 subnet. The service ID of this service group must be 80 to match the service ID added to the server.

config system settings set wccp-cache-engine enable

end

config system wccp edit 80 set cache-id 10.31.101.1 set router-list 10.31.101.100

set ports 443 set protocol 6

end

Example WCCP server and client configuration for caching HTTP and HTTPS sessions

You could do this by configuring two WCCP service groups as described in the previous examples. Or you could use the following commands to configure one service group for both types of traffic. The example also caches HTTP sessions on port 8080.

Enter the following command to add a service group to a WCCP server that caches HTTP sessions on ports 80

and 8080 and HTTPS sessions on port 443. Both of these protocols use protocol number 6. The IP address of the server is 10.31.101.100 and the WCCP clients are on the 10.31.101.0 subnet. The service ID of this service group is 90.

config system wccp edit 90

service groups, service numbers, service IDs and well known services

set router-id 10.31.101.100 set server-list 10.31.101.0 255.255.255.0

set ports 443 80 8080 set protocol 6

end

Enter the following commands to configure a FortiGate unit to operate as a WCCP client and add a service group that configures client to cache HTTP sessions on port 80 and 8080 and HTTPS sessions on port 443. The IP address of the server is 10.31.101.100 and IP address of this WCCP clients is 10.31.101.1 subnet. The service ID of this service group must be 90 to match the service ID added to the server.

config system settings set wccp-cache-engine enable

end config system wccp edit 90 set cache-id 10.31.101.1 set router-list 10.31.101.100 set ports 443 80 8080 set protocol 6

end

Other WCCP service group options

In addition to using WCCP service groups to define the types of traffic to be cached by WCCP the following options are available for servers and clients.

Server configuration options

The server configuration must include the router-id, which is the WCCP server IP address. This is the IP address of the interface that the server uses to communicate with WCCP clients.

The group-address is used for multicast WCCP configurations to specify the multicast addresses of the clients.

The server-list defines the IP addresses of the WCCP clients that the server can connect to. Often the server list can be the address of the subnet that contains the WCCP clients.

The authentication option enables or disables authentication for the WCCP service group. Authentication must be enabled on all servers and clients in a service group and members of the group must have the same password.

The forward-method option specifies the protocol used for communication between the server and clients. The default forwarding method is GRE encapsulation. If required by your network you can also select to use unencapsulated layer-2 packets instead of GRE or select any to allow both. The return-method allows you to specify the communication method from the client to the server. Both GRE and layer-2 are supported.

The assignment-method determines how the server load balances sessions to the clients if there are multiple clients. Load balancing can be done using hashing or masking.

Client configuration options

The client configuration includes the cache-id which is the IP address of the FortiGate interface of the client that communicates with WCCP server. The router-list option is the list of IP addresses of the WCCP servers in the WCCP service group.

 

Example caching HTTP sessions on port 80

The ports option lists the port numbers of the sessions to be cached by the client and the protocol sets the protocol number of the sessions to be cached. For TCP sessions the protocol is 6.

The service-type option can be auto, dynamic or standard. Usually you would not change this setting.

The client configuration also includes options to influence load balancing including the primary-hash, priority, assignment-weight and assignment-bucket-format.

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WCCP Concepts

The Web Cache Communication Protocol (WCCP) can be used to provide web caching with load balancing and fault tolerance. In a WCCP configuration, a WCCP server receives HTTP requests from user’s web browsers and redirects the requests to one or more WCCP clients. The clients either return cached content or request new content from the destination web servers before caching it and returning it to the server which in turn returns the content to the original requestor. If a WCCP configuration includes multiple WCCP clients, the WCCP server load balances traffic among the clients and can detect when a client fails and failover sessions to still operating clients. WCCP is described by the Web Cache Communication Protocol Internet draft.

The sessions that are cached by WCCP depend on the configuration of the WCCP clients. If the client is a FortiGate unit, you can configure the port numbers and protocol number of the sessions to be cached. For example, to cache HTTPS traffic on port 443 the WCCP client port must be set to 443 and protocol must be set to

6. If the WCCP client should also cache HTTPS traffic on port 993 the client ports option should include both port 443 and 993.

On a FortiGate unit, WCCP sessions are accepted by a security policy before being cached. If the security policy that accepts sessions that do not match the port and protocol settings in the WCCP clients the traffic is dropped.

WCCP is configured per-VDOM. A single VDOM can operate as a WCCP server or client (not both at the same time). FortiGate units are compatible with third-party WCCP clients and servers. If a FortiGate unit is operating as an Internet firewall for a private network, you can configure it to cache and serve some or all of the web traffic on the private network using WCCP by adding one or more WCCP clients, configuring WCCP server settings on the FortiGate unit and adding WCCP security policies that accept HTTP session from the private network.

FortiGate units support WCCPv1 and WCCPv2. A FortiGate unit in NAT/Route or transparent mode can operate as a WCCP server. To operate as a WCCP client a FortiGate unit must be in NAT/Route mode. FortiGate units communicate between WCCP servers and clients over UDP port 2048. This communication can be encapsulated in a GRE tunnel or just use layer 2 forwarding.

WCCP configuration overview

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Web Cache Configuration

Forwarding URLs to forwarding servers and exempting web sites from web caching

You can go to Network > Explicit Proxy and use the URL match list to forward URL patterns to forwarding servers and create a list of URLs that are exempt from web caching.

Forwarding URLs and URL patterns to forwarding servers

As part of configuring the explicit web proxy you can configure proxy chaining by adding web proxy forwarding servers. See Proxy chaining (web proxy forwarding servers) .

You can then use the URL match list to always forward explicit web proxy traffic destined for configured URLs or URL patterns to one of these forwarding servers. For example, you might want to forward all traffic for a specific country to a proxy server located in that country.

To forward traffic destined for a URL to a forwarding server that you have already added, go to Network > Explicit Proxy and select Create New. Add a name for the URL match entry and enter the URL or URL pattern. You can use wildcards such as * and ? and you can use a numeric IP address. Select Forward to Server and select a web proxy forwarding server from the list.

You can also exempt the URL or URL pattern from web caching.

Use the following command to forward all .ca traffic to a proxy server and all .com traffic to another proxy server.

config web-proxy url-match edit “com” set forward-server “server-commercial” set url-pattern “com”

next edit “ca” set forward-server “server-canada” set url-pattern “ca”

next

edit “www.google.ca” set cache-exemption enable set url-pattern “www.google.ca”

next

end

Exempting web sites from web caching

You may want to exempt some URLs from web caching for a number of reasons. For example, if your users access websites that are not compatible with FortiGate web caching you can add the URLs of these web sites to the web caching exempt list. You can add URLs and numeric IP addresses to the web cache exempt list.

You can also add URLs to the web cache exempt list by going to Network > Explicit Proxy, going to the URL Match List

Configuration             Forwarding URLs to forwarding servers and exempting web sites from web caching

and selecting Create New. Add a URL pattern to be exempt and select Exempt from Cache.

You can also add URLs and addresses to be exempt from caching using the CLI. Enter the following command to add www.example.com to the web cache exempt list:

config web-proxy url-match set cache-exemption enable set url-pattern www.example.com

end

Exempting specific files from caching

You can exempt files from being cached, so long as you specify its full URL. Enter the following command to add the URL, with the file extension (in this example, .exe), to the web cache exempt list:

config web-proxy url-match edit “exe” set url-pattern “iavs9x.u.avast.com/custom/iavs9x/20160613t1237z/avast_free_ antivirus_setup_online.exe”

set cache-exemption enable

next end

Monitoring Web caching performance                                                                                Web Cache

Monitoring Web caching performance

The web cache monitor shows the percentage of web cache requests that retrieved content from the cache (hits) and the percentage that did not receive content from the cache (misses). A higher the number of hits usually indicates that the web cache is being more effective at reducing WAN traffic.

The web cache monitor also shows a graph of web traffic on the WAN and LAN. A lower WAN line on the graph indicates the web cache is reducing traffic on the WAN. The web cache monitor also displays the total number of web requests processed by the web cache.

To view the web cache monitor, go to Monitor > Cache Monitor.

Web cache monitor

Example Web caching of HTTP and HTTPS Internet content for users on an internal network

This example describes how to configure web caching of HTTP and HTTPS for users on a private network connecting to the Internet.

Network topology and assumptions

This example includes a client network with subnet address 10.31.101.0 connecting to web servers on the

Internet. All of the users on the private network access the Internet though a single general security policy on the FortiGate unit that accepts all sessions connecting to the Internet. Web caching for HTTP and HTTPS traffic is added to this security policy.

Since users on the private network have unrestricted access to the Internet and can be accessing many web servers the webcache-https is set to any and users may see error messages on their web browsers when accessing HTTPS content.

The GUI is less versatile than the CLI so the example instructions for the GUI give settings for one port for each protocol, while the CLI example shows how to use multiple ports.

 

Example Web caching of HTTP and HTTPS Internet content for users on an internal network

The example also describes how to configure the security policy to cache HTTP traffic on port 80 and 8080 in the CLI, by adding a proxy options profile that looks for HTTP traffic on TCP ports 80 and 8080. The example also describes how to configure the security policy to cache HTTPS traffic on port 443 and 8443 using the same proxy options profile.

Example web caching topology

General configuration steps

This section breaks down the configuration for this example into smaller procedures. For best results, follow the procedures in the order given:

1. Add HTTP web caching to the security policy that all users on the private network use to connect to the Internet.
2. Add HTTPS web caching.
3. Add a protocol options profile to look for HTTP traffic on ports 80 and 8080 and HTTPS traffic on ports 443 and 8443 and add this protocol options profile to the security policy.

If you perform any additional actions between procedures, your configuration may have different results.

Configuration Steps – web-based manager

Use the following steps to configure the example configuration from the FortiGate web-based manager.

To add HTTP web caching to a security policy

1. Go to Policy & Objects > IPv4 Policyand add a security policy that allows all users on the internal network to access the Internet.

Incoming Interface	Internal
Outgoing Interface	wan1
Source	all
Destination	all
Schedule	always
Service	ALL
Action	ACCEPT

2. Toggle NAT to enabled, and select Use Outgoing Interface Address.
3. Turn on Web cache.
4. Select OK.

Web caching of HTTP and HTTPS Internet content for users on an internal

network

To add HTTPS web caching

1. From the CLI enter the following command to add HTTPS web caching to the policy.

Assume the index number of the policy is 5.

config firewall policy edit 5 set webcache-https any

end

To cache HTTP traffic on port 80 and HTTPS on 8443

1. Go to Network > Explicit Proxy and edit the Explicit Proxy options profile. 2. Under Explicit Web Proxy , l For the HTTP port, enter 80.

l For HTTPS port, select Specify and enter 8443 in the field.

3. Click on Apply.

Configuration Steps – CLI

Use the following steps to configure the example configuration from the FortiGate CLI.

To add HTTP and HTTPS web caching to a security policy

1. Enter the following command to add a security policy that allows all users on the internal network to access the Internet and that includes web caching of HTTP and HTTPS traffic.

config firewall policy edit 0 set srcintf internal set srcaddr all set dstintf wan1 set distinf all set schedule always set service ANY set action accept set nat enable set webcache enable set webcache-https any

end

To cache HTTP traffic on port 80 and 8080 and HTTPS traffic on ports 443 and 8443

1. Enter the following command to edit the default proxy options profile to configure it to look for HTTP traffic on ports 80 and 8080:

config firewall profile-protocol-options edit default config http set status enable set ports 80 8080

end

2. Enter the following command to edit the certification-inspection SSL SSH options profile to configure it to look for HTTPS traffic on ports 443 and 8443:

config firewall ssl-ssh-profile edit certificate-inspection config https set status certificate-inspection

set ports 443 8443 end

3. Enter the following command to add the default proxy options profile and the certificate-inspection SSL SSH profile to the firewall policy.

config firewall policy edit 5 set utm-status enable set profile-protocol-options default set ssl-ssh-profile certificate-inspection end

Example reverse proxy web caching and SSL offloading for an Internet web server using a static one-to-one virtual IP

This section describes configuring SSL offloading for a reverse proxy web caching configuration using a static one-to-one firewall virtual IP (VIP). While the static one-to-one configuration described in this example is valid, its also common to change the destination port of the unencrypted HTTPS traffic to a commonly used HTTP port such as 8080 using a port forwarding virtual IP.

Network topology and assumptions

In this configuration, clients on the Internet use HTTP and HTTPS to browse to a web server that is behind a FortiGate unit. A policy added to the FortiGate unit forwards the HTTP traffic to the web server. The policy also offloads HTTPS decryption and encryption from the web server so the web server only sees HTTP traffic.

The FortiGate unit also caches HTTP and HTTPS pages from the web server so when users access cached pages the web server does not see the traffic. Replies to HTTPS sessions are encrypted by the FortiGate unit before returning to the clients.

In this configuration, the FortiGate unit is operating as a web cache in reverse proxy mode. Reverse proxy caches can be placed directly in front of a web server. Web caching on the FortiGate unit reduces the number of requests that the web server must handle, therefore leaving it free to process new requests that it has not serviced before.

Using a reverse proxy configuration:

l avoids the capital expense of additional web servers by increasing the capacity of existing servers l serves more requests for static content from web servers l serves more requests for dynamic content from web servers l reduces operating expenses including the cost of bandwidth required to serve content l accelerates the response time of web servers and of page download times to end users.

 

one-to-one virtual IP

When planning a reverse proxy implementation, the web server’s content should be written so that it is “cache aware” to take full advantage of the reverse proxy cache.

In reverse proxy mode, the FortiGate unit functions more like a web server for clients on the Internet. Replicated content is delivered from the proxy cache to the external client without exposing the web server or the private network residing safely behind the firewall.

In this example, the site URL translates to IP address 192.168.10.1, which is the port2 IP address of the FortiGate unit. The port2 interface is connected to the Internet.

This example assumes that all HTTP traffic uses port 80 and all HTTPS traffic uses port 443.

The FortiGate unit includes the web server CA and an SSL server configuration for IP address 172.10.20.30 and port to 443. The name of the file containing the CA is Rev_Proxy_Cert_1.crt.

The destination address of incoming HTTP and HTTPS sessions is translated to the IP address of the web server using a static one-to-one virtual IP that performs destination address translation (DNAT) for the HTTP packets. The DNAT translates the destination address of the packets from 192.168.10.1 to 172.10.20.30 but does not change the destination port number.

When the SSL server on the FortiGate unit decrypts the HTTPS packets their destination port is changed to port 80.

Reverse proxy web caching and SSL offloading for an Internet web server using static one-to-one virtual IPs

General configuration steps

This section breaks down the configuration for this example into smaller procedures. For best results, follow the procedures in the order given:

1. Configure the FortiGate unit as a reverse proxy web cache server.
2. Configure the FortiGate unit for SSL offloading of HTTPS traffic.
3. Add an SSL server to offload SSL encryption and decryption for the web server.

Also note that if you perform any additional actions between procedures, your configuration may have different results.

Configuration steps – web-based manager

To configure the FortiGate unit as a reverse proxy web cache server

1. Go to Policy & Objects > Virtual IPsand select Create New to add a static NAT virtual IP that translates destination IP addresses from 192.168.10.1 to 172.10.20.30 (and does not translate destination ports):

VIP Type	IPv4
Name	Reverse_proxy_VIP
Interface	port2
Type	Static NAT
Optional Filters	Do not select.
External IP Address/Range	192.168.10.1
Mapped IP Address/Range	172.10.20.30
Port Forwarding	Do not select.

2. Select OK.
3. Go to Policy & Objects > IPv4 Policy and select Create New to add a port2 to port1 security policy that accepts HTTP and HTTPS traffic from the Internet.

Do not select security profiles. Set the destination address to the virtual IP. You do not have to enable NAT.

Incoming Interface	port2
Outgoing Interface	port1
Source	all
Destination	Reverse_proxy_VIP
Schedule	always
Service	HTTP HTTPS
Action	ACCEPT

4. Turn on Web Cache.
5. Select OK.
6. From the CLI enter the following command to add HTTPS web caching to the security policy

Assume the index number of the policy is 5.

config firewall policy edit 5 set webcache-https ssl-server

one-to-one virtual IP

end

To configure the FortiGate unit to offload SSL encryption and cache HTTPS content

1. Go to System > Certificates and select Import to import the web server’s CA.

For Type, select Local Certificate. Select the Browse button to locate the file (example file name: Rev_Proxy_

Cert_1.crt).

The certificate key size must be 1024 or 2048 bits. 4096-bit keys are not supported.

2. Select OK to import the certificate.
3. From the CLI, enter the following command to add the SSL server and to add the server’s certificate to the SSL server.

The SSL server ip must match the destination address of the SSL traffic after being translated by the virtual IP (172.10.20.30) and the SSL server port must match the destination port of the SSL traffic (443). The SSL server operates in half mode since it performs a single-step conversion (HTTPS to HTTP or HTTP to HTTPS).

config firewall ssl-server edit rev_proxy_server set ip 172.10.20.30 set port 443 set ssl-mode half set ssl-cert Rev_Proxy_Cert_1 end

Configuration steps – CLI

To configure the FortiGate unit as a reverse proxy web cache server

1. Enter the following command to add a static NAT virtual IP that translates destination IP addresses from 192.168.10.1 to 172.10.20.30 (and does not translate destination ports):

config firewall vip edit Reverse_proxy_VIP set extintf port2 set type static-nat set extip 192.168.10.1 set mappedip 172.10.20.30

end

2. Enter the following command to add a port2 to port1 security policy that accepts HTTP and HTTPS traffic from the Internet. Enable web caching and HTTPS web caching.

Do not select security profiles. Set the destination address to the virtual IP. You do not have to enable NAT.

config firewall policy edit 0 set srcintf port2 set srcaddr all set dstintf port1 set dstaddr Reverse_proxy_VIP set schedule always set service HTTP HTTPS set action accept

set webcache enable set webcache-https ssl-server

end

To add an SSL server to offload SSL encryption and decryption for the web server

1. Place a copy of the web server’s CA (file name Rev_Proxy_Cert_1.crt) in the root folder of a TFTP server.
2. Enter the following command to import the web server’s CA from a TFTP server. The IP address of the TFTP server is 10.31.101.30:

execute vpn certificate local import tftp Rev_Proxy_Cert_1.crt 10.31.101.30 The certificate key size must be 1024 or 2048 bits. 4096-bit keys are not supported.

3. From the CLI, enter the following command to add the SSL server.

The SSL server ip must match the destination address of the SSL traffic after being translated by the virtual IP (172.10.20.30) and the SSL server port must match the destination port of the SSL traffic (443). The SSL server operates in half mode since it performs a single-step conversion (HTTPS to HTTP or HTTP to HTTPS).

config firewall ssl-server edit rev_proxy_server set ip 172.10.20.30 set port 443 set ssl-mode half set ssl-cert Rev_Proxy_Cert_1

end

4. Configure other ssl-server settings that you may require for your configuration.

 

one-                   WCCP

to-one virtual IP                                                                                                                                      Concepts

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Web Cache Concepts

FortiGate web caching is a form of object caching that accelerates web applications and web servers by reducing bandwidth usage, server load, and perceived latency. Web caching supports caching of HTTP 1.0 and HTTP 1.1 web sites. See RFC 2616 for information about web caching for HTTP 1.1.

Web caching supports caching of Flash content over HTTP but does not cache audio and video streams including Flash videos and streaming content that use native streaming protocols such as RTMP.

The first time a file is received by web caching it is cached in the format it is received in, whether it be compressed or uncompressed. When the same file is requested by a client but in a different compression format, the cached file is converted to the new compressed format before being sent to the client.

There are three significant advantages to using web caching to improve HTTP and WAN performance:

• reduced bandwidth consumption because fewer requests and responses go over the WAN or Internet. l reduced web server load because there are fewer requests for web servers to handle.
• reduced latency because responses for cached requests are available from a local FortiGate unit instead of from across the WAN or Internet.

You can use web caching to cache any web traffic that passes through the FortiGate unit, including web pages from web servers on a LAN, WAN or on the Internet. You apply web caching by enabling the web caching option in any security policy. When enabled in a security policy, web caching is applied to all HTTP sessions accepted by the security policy. If the security policy is an explicit web proxy security policy, the FortiGate unit caches explicit web proxy sessions.

Turning on web caching for HTTP and HTTPS traffic

Web caching can be applied to any HTTP or HTTPS traffic by enabling web caching in a security policy that accepts the traffic. This includes IPv4, IPv6, WAN optimization and explicit web proxy traffic. Web caching caches all HTTP traffic accepted by a policy on TCP port 80.

You can add web caching to a policy to:

• Cache Internet HTTP traffic for users on an internal network to reduce Internet bandwidth use. Do this by selecting the web cache option for security policies that allow users on the internal network to browse web sites on the

Internet.

• Reduce the load on a public facing web server by caching objects on the FortiGate unit. This is a reverse proxy with web caching configuration. Do this by selecting the web cache option for a security policy that allows users on the Internet to connect to the web server.
• Cache outgoing explicit web proxy traffic when the explicit proxy is used to proxy users in an internal network who are connecting to the web servers on the Internet. Do this by selecting the web cache option for explicit web proxy security policies that allow users on the internal network to browse web sites on the Internet.
• Combine web caching with WAN optimization. You can enable web caching in any WAN optimization security policy. This includes manual, active, and passive WAN optimization policies and WAN optimization tunnel policies.

Turning on web caching for HTTPS traffic

You can enable web caching on both the client-side and the server-side FortiGate units or on just one or the other. For optimum performance you can enable web caching on both the client-side and server-side FortiGate units. In this way only uncached content is transmitted through the WAN optimization tunnel. All cached content is access locally by clients from the client side FortiGate unit.

One important use for web caching is to cache software updates (for example, Windows Updates or iOS updates. When updates occur a large number of users may all be trying to download these updates at the same time. Caching these updates will be a major performance improvement and also have a potentially large impact on reducing Internet bandwidth use. You may want to adjust the maximum cache object size to make sure these updates are cached. See Turning on web caching for HTTP and HTTPS traffic on page 270.

Turning on web caching for HTTPS traffic

Web caching can also cache the content of HTTPS traffic on TCP port 443. With HTTPS web caching, the FortiGate unit receives the HTTPS traffic on behalf of the client, opens up the encrypted traffic and extracts content to be cached. Then FortiGate unit re-encrypts the traffic and sends it on to its intended recipient. It is very similar to a man-in-the-middle attack.

You enable HTTPS web caching from the CLI in a security policy or an explicit proxy policy that accepts the traffic to be cached using webcache-https. For a firewall policy:

config firewall policy edit 0 .

. . set webcache enable set webcache-https any .

.

.

end

For an explicit web proxy policy:

config firewall proxy-policy edit 0 set proxy explicit-web .

. . set webcache enable set webcache-https any .

.

. end

Turning on web caching for HTTPS traffic

The any setting causes the FortiGate unit to re-encrypt the traffic with the FortiGate unit’s certificate rather than the original certificate. This configuration can cause errors for HTTPS clients because the name on the certificate does not match the name on the web site.

You can stop these errors from happening by configuring HTTPS web caching to use the web server’s certificate by setting webcache-https to ssl-server. This option is available for both firewall policies and explicit web proxy policies.

config firewall policy edit 0 .

. . set webcache enable set webcache-https ssl-server .

.

.

end

The ssl-server option causes the FortiGate unit to re-encrypt the traffic with a certificate that you imported into the FortiGate unit. You can add certificates using the following command:

config firewall ssl-server edit corporate-server set ip <Web-Server-IP> set port 443 set ssl-mode { full | half} set ssl-cert <Web-Server-Cert>

end Where:

Web-Server-IP is the web server’s IP address.

Web-Server-Cert is a web server certificate imported into the FortiGate unit.

The SSL server configuration also determines whether the SSL server is operating in half or full mode and the port used for the HTTPS traffic.

You can add multiple SSL server certificates in this way. When web caching processing an SSL stream if it can find a certificate that matches the web server IP address and port of one of the added SSL servers; that certificate is used to encrypt the SSL traffic before sending it to the client. As a result the client does not generate SSL certificate errors.

Web caching uses the FortiGate unit’s FortiASIC to accelerate SSL decryption/encryption performance.

Full mode SSL server configuration

The ssl-mode option determines whether the SSL server operates in half or full mode. In full mode the FortiGate unit performs both decryption and encryption of the HTTPS traffic. The full mode sequence is shown below.

Turning on web caching for HTTPS traffic

Full mode SSL server configuration

In full mode the FortiGate unit is acting as a man in the middle, decrypting and encrypting the traffic. So both the client and the web server see encrypted packets.

Usually the port of the encrypted HTTPS traffic is always 443. However, in the SSL server configuration you can set the port used for HTTPS traffic. This port is not altered by the SSL Server. So for example, if the SSL Server receives HTTPS traffic on port 443, the re-encrypted traffic forwarded to the FortiGate unit to the server or client will still use port 443.

Half mode SSL server configuration

In half mode, the FortiGate unit only performs one encryption or decryption action. If HTTP packets are received, the half mode SSL server encrypts them and converts them to HTTPS packets. If HTTPS packets are received, the SSL server decrypts them and converts them to HTTP packets.

Half mode SSL server configuration

In half mode, the FortiGate unit is acting like an SSL accelerator, offloading HTTPS decryption from the web server to the FortiGate unit. Since FortiGate units can accelerate SSL processing, the end result could be improved web site performance.

Usually the port of the encrypted traffic is always 443. However, in the SSL server configuration you can set the port used for HTTPS traffic. No matter what port is used for the HTTPS traffic, the decrypted HTTP traffic uses port 80.

Changing the ports on which to look for HTTP and HTTPS traffic to cache

Changing the ports on which to look for HTTP and HTTPS traffic to cache

By default FortiOS assumes HTTP traffic uses TCP port 80 and HTTPS traffic uses port 443. So web caching caches all HTTP traffic accepted by a policy on TCP port 80 and all HTTPS traffic on TCP port 443. If you want to cache HTTP or HTTPS traffic on other ports, you can enable security profiles for the security policy and configure a proxy options profile to that looks for HTTP and HTTPS traffic on other TCP ports. To configure a proxy options profile go to Network > Explicit Proxy.

Setting the HTTP port to Any in a proxy options profile is not compatible with web caching. If you set the HTTP port to any, web caching only caches HTTP traffic on port 80.

Web caching and HA

You can configure web caching on a FortiGate HA cluster. The recommended best practice HA configuration for web caching is active-passive mode. When the cluster is operating, all web caching sessions are processed by the primary unit only. Even if the cluster is operating in active-active mode, HA does not load-balance web caching sessions.

In a cluster, only the primary unit stores the web cache database. The databases is not synchronized to the subordinate units. So, after a failover, the new primary unit must build its web cache.

Web caching and memory usage

To accelerate and optimize disk access and to provide better throughput and less latency, web caching uses provisioned memory to reduce disk I/O and increase disk I/O efficiency. In addition, web caching requires a small amount of additional memory per session for comprehensive flow control logic and efficient traffic forwarding.

When web caching is enabled you will see a reduction in available memory. The reduction increases when more web caching sessions are being processed. If you are thinking of enabling web caching on an operating FortiGate unit, make sure its memory usage is not maxed out during high traffic periods.

In addition to using the system dashboard to see the current memory usage you can use the get test wad 2 command to see how much memory is currently being used by web caching. See get test {wad | wccpd} <test_ level> on page 1 for more information.

Changing web cache settings

In most cases, the default settings for the WAN optimization web cache are acceptable. However, you may want to change them to improve performance or optimize the cache for your configuration. To change these settings, go to WAN Opt. & Cache > Settings.

From the FortiGate CLI, you can use the config wanopt webcache command to change these WAN optimization web cache settings.

Changing web cache settings

Always revalidate

Select to always revalidate requested cached objects with content on the server before serving them to the client.

Max cache object size

Set the maximum size of objects (files) that are cached. The default size is 512000 KB and the range is 1 to 4294967 KB. This setting determines the maximum object size to store in the web cache. Objects that are larger than this size are still delivered to the client but are not stored in the FortiGate web cache.

For most web traffic the default maximum cache object size is recommended. However, since web caching can also cache larger objects such as Windows updates, Mac OS updates, iOS updates or other updates delivered using HTTP you might want to increase the object size to make sure these updates are cached. Caching these updates can save a lot of Internet bandwidth and improve performance when major updates are released by these vendors.

Negative response duration

Set how long in minutes that the FortiGate unit caches error responses from web servers. If error responses are cached, then subsequent requests to the web cache from users will receive the error responses regardless of the actual object status.

The default is 0, meaning error responses are not cached. The content server might send a client error code (4xx HTTP response) or a server error code (5xx HTTP response) as a response to some requests. If the web cache is configured to cache these negative responses, it returns that response in subsequent requests for that page or image for the specified number of minutes.

Fresh factor

Set the fresh factor as a percentage. The default is 100, and the range is 1 to 100%. For cached objects that do not have an expiry time, the web cache periodically checks the server to see if the objects have expired. The higher the Fresh Factor the less often the checks occur.

For example, if you set the Max TTL value and Default TTL to 7200 minutes (5 days) and set the Fresh Factor to 20, the web cache check the cached objects 5 times before they expire, but if you set the Fresh Factor to 100, the web cache will check once.

Max TTL

The maximum amount of time (Time to Live) an object can stay in the web cache without the cache checking to see if it has expired on the server. The default is 7200 minutes (120 hours or 5 days) and the range is 1 to 5256000 minutes (5256000 minutes in a year).

Changing web cache settings

Min TTL

The minimum amount of time an object can stay in the web cache before the web cache checks to see if it has expired on the server. The default is 5 minutes and the range is 1 to 5256000 minutes (5256000 minutes in a year).

Default TTL

The default expiry time for objects that do not have an expiry time set by the web server. The default expiry time is 1440 minutes (24 hours) and the range is 1 to 5256000 minutes (5256000 minutes in a year).

Proxy FQDN

The fully qualified domain name (FQDN) for the proxy server. This is the domain name to enter into browsers to access the proxy server. This field is for information only can be changed from the explicit web proxy configuration.

Max HTTP request length

The maximum length of an HTTP request that can be cached. Larger requests will be rejected. This field is for information only can be changed from the explicit web proxy configuration.

Max HTTP message length

The maximum length of an HTTP message that can be cached. Larger messages will be rejected. This field is for information only can be changed from the explicit web proxy configuration.

Ignore

Select the following options to ignore some web caching features.

If-modified-since

By default, if the time specified by the if-modified-since (IMS) header in the client’s conditional request is greater than the last modified time of the object in the cache, it is a strong indication that the copy in the cache is stale. If so, HTTP does a conditional GET to the Overlay Caching Scheme (OCS), based on the last modified time of the cached object. Enable ignoring if-modified-since to override this behavior.

HTTP 1.1 conditionals

HTTP 1.1 provides additional controls to the client over the behavior of caches toward stale objects. Depending on various cache-control headers, the FortiGate unit can be forced to consult the OCS before serving the object from the cache. For more information about the behavior of cache-control header values, see RFC 2616.Enable ignoring HTTP 1.1 Conditionals to override this behavior.

Changing web cache settings

Pragma-no-cache

Typically, if a client sends an HTTP GET request with a pragma no-cache (PNC) or cache-control no-cache header, a cache must consult the OCS before serving the content. This means that the FortiGate unit always re-fetches the entire object from the OCS, even if the cached copy of the object is fresh. Because of this behavior, PNC requests can degrade performance and increase server-side bandwidth utilization. However, if you enable ignoring Pragma-no-cache, then the PNC header from the client request is ignored. The FortiGate unit treats the request as if the PNC header is not present.

IE Reload

Some versions of Internet Explorer issue Accept / header instead of Pragma no-cache header when you select Refresh. When an Accept header has only the / value, the FortiGate unit treats it as a PNC header if it is a type-N object. Enable ignoring IE reload to cause the FortiGate unit to ignore the PNC interpretation of the Accept / header.

Cache Expired Objects

Applies only to type-1 objects. When this option is selected, expired type-1 objects are cached (if all other conditions make the object cacheable).

Revalidated Pragma-no-cache

The pragma-no-cache (PNC) header in a client’s request can affect how efficiently the FortiGate unit uses bandwidth. If you do not want to completely ignore PNC in client requests (which you can do by selecting to ignore Pragma-no-cache, above), you can nonetheless lower the impact on bandwidth usage by selecting Revalidate Pragma-no-cache.

When you select Revalidate Pragma-no-cache, a client’s non-conditional PNC-GET request results in a conditional GET request sent to the OCS if the object is already in the cache. This gives the OCS a chance to return the 304 Not Modified response, which consumes less server-side bandwidth, because the OCS has not been forced to otherwise return full content.

By default, Revalidate Pragma-no-cache is disabled and is not affected by changes in the top-level profile.

Most download managers make byte-range requests with a PNC header. To serve such requests from the cache, you should also configure byte-range support when you configure the Revalidate pragma-no-cache option.

 

Forwarding URLs to forwarding servers and exempting web sites from web caching                Web Cache

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