WCCP Configuration

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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