Basic BGP network topology
Assumptions
The basic BGP configuration procedure follows these assumptions:
- ISP1 is the preferred route, and ISP2 is the secondary route
- All basic configuration can be completed in both GUI and CLI
- Only one AS is used for the Company
For these reasons this example configuration does not include:
- Bi-directional forwarding detection (BFD)
- Route maps
- Access lists
- Changing redistribution defaults — make link when example is set up
- IPv6
For more information on these features, see the corresponding section.
Configuring the FortiGate unit
In this topology, the FortiGate unit is the link between the Company Network and the ISP network. The FortiGate unit is the only BGP router on the Company Network, but there is at least one other BGP router on the ISP Network — there may be more but we don’t have that information.
As mentioned in the general configuration steps, the ISP must be notified of the Company’s BGP router configuration when complete as it will need to add the FortiGate BGP router as a neighbor router on its domain. This step is required for the FortiGate unit to receive BGP routing updates from the ISP network and outside networks.
If the ISP has any special BGP features enabled such as graceful restart, or route dampening that should be determined up front so those features can be enabled on the FortiGate unit.
To configure the FortiGate unit as a BGP router
1. Configure interfaces and default routes
2. Configure firewall services, addresses, and policies
3. Set the FortiGate BGP information
4. Add the internal network to the AS
5. Additional FortiGate BGP configuration
Configure interfaces and default routes
The FortiGate unit is connected to three networks — Company Network on the internal interface, ISP1 Network on external1interface, and ISP2 on external2 interface.
This example uses basic interface settings. Check with your ISP to determine if additional settings are required such as setting the maximum MTU size, or if gateway detection is supported.
High end FortiGate units do not have interfaces labeled Internal, or External. Instead, for clarity’s sake, we are using the alias feature to name interfaces for these roles.
Default routes to both external interfaces are configured here as well. Both are needed in case one goes offline. ISP1 is the primary connection and has a smaller administrative distance so it will be preferred over ISP2. Both distances are set low so they will be preferred over any learned routes.
To configure the FortiGate interfaces – web-based manager
1. Go to System > Network > Interface.
2. Edit port 1 (internal) interface.
3. Set the following information, and select OK.
Alias internal
IP/Network Mask 10.11.101.110/255.255.255.0
Administrative Access HTTPS SSH PING
Description Company internal network
Administrative Status Up
4. Edit port 2 (external1) interface.
5. Set the following information, and select OK.
Alias external1
IP/Network Mask 172.21.111.5/255.255.255.0
Administrative Access HTTPS SSH PING
Description ISP1 External BGP network
Administrative Status Up
6. Edit port 3 (external2) interface.
7. Set the following information, and select OK.
Alias external2
IP/Network Mask 172.22.222.5/255.255.255.0
Administrative Access HTTPS SSH PING
Description ISP2 External BGP network
Administrative Status Up
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Hi Mike,
if i configure the following on fortigate1:
config router bgp
set as 65000
set router-id 10.2.2.254
config neighbor
edit “10.2.2.253”
set next-hop-self enable
set remote-as 65000
set send-community6 disable
next
config redistribute “static”
set status enable
end
fortigate2 should get the default route 0.0.0.0 0.0.0.0 from fortigate1 as it is static ?
how can i redistribute the default route(fortigate1) to fortigate2 ?
thanks
regards
There is a really good KB article that explains how to do this. You can find it here
If you want to redistribute static routes you would enable the following
config router bgp
config redistribute static
set status enable
end
end
An example of the config would be like this
config router prefix-list
edit “only_dflt”
config rule
edit 1
set prefix 0.0.0.0 0.0.0.0
unset ge
unset le
next
end
next
end
config router route-map
edit “only_default_route”
config rule
edit 1
set match-ip-address “only_dflt”
next
end
next
end
config router bgp
set as 2
config neighbor
edit 10.142.0.110
set remote-as 1
set route-map-in “only_default_route”
next
end
set router-id 10.142.0.205
end
Let me know if this helped answer your question!
Thanks!
Hi,
thanks for the link and example, got it working!
Regards
Awesome to hear Piccolo!
config router bgp
set as 65041
set router-id 162.53.156.138
config neighbor
edit “10.104.55.1”
set ebgp-enforce-multihop enable
set soft-reconfiguration enable
set remote-as 64699
set send-community6 disable
next
edit “10.104.55.2”
set ebgp-enforce-multihop enable
set soft-reconfiguration enable
set remote-as 64699
set send-community6 disable
next
i am trying to accomplish above but i can see only one neighbour is establish and other is in ACTIVE state…
So you see both neighbors but only one is active?