Configuring a VRF to work properly for FRR
Linux Kernel Documentation
Special Consideration of Default Route in the VRF
Set the default route for the table (and hence default route for the VRF).
ip route add table 10 unreachable default metric 4278198272
high metric value ensures that the default unreachable route can be overridden by a routing protocol suite. FRRouting interprets kernel metrics as a combined admin distance (upper byte) and priority (lower 3 bytes). Thus the above metric translates to [255/8192].
Tutorial for VRF's
router bgp 64900 vrf vrf1012 bgp router-id 192.0.2.1 no bgp default ipv4-unicast neighbor 192.0.2.3 remote-as 65321 ! address-family ipv4 unicast neighbor 192.0.2.3 activate exit-address-family !
To establish a session with a neighbor in a VRF, FRRouting needs to be able to listen on the BGP TCP port in the VRF. In order to be allowed to do so by the kernel, the following sysctl is required:
sysctl -w net.ipv4.tcp_l3mdev_accept=1
Relates to Issue #1177