How to enable different VRFs to communicate

[CiscoBrownBelt]

So if I want let's say VRF100 to talk to only VRF200 and vice versa, I believe I read you have to leak routes via using RD parameters. I am a bit confused on what numbers/parameters or how I configure this. Any help guys/gals?

[mbarnovsky1]

Are you doing this between two VRFs on the same device? I know you can leak from a VRF over to the Global routing table via the "global" keyword at the end of a static route, or you can create a route-map with an ACL/Prefix-list that permits the desired route (I believe this is done on the interface) and use the "set global" command to permit it to the global table.

To go directly from one VRF to the next on the same box would be tricky. I think you could accept the RD on the other VRF and then prefix-list/ACL all but the desired route off there, but I have never tried that. It's more just speculation. Maybe worth trying in a lab if that sounds like something you could use?

Cisco has some good documentation on the first example I mentioned. I'd have to really dig around on for anything on the ladder.

[CiscoBrownBelt]

Awesome I will look into it and post an update.

[omz]

Try this.

ip vrf VRF100

rd 1:1

route-target export 1:1

route-target import 2:2

!

ip vrf VRF200

rd 2:2

route-target export 2:2

route-target import 1:1

!

router bgp 65000

no synchronization

bgp log-neighbor-changes

no auto-summary

!

address-family ipv4 vrf VRF100

redistribute connected

no synchronization

exit-address-family

!

address-family ipv4 vrf VRF200

redistribute connected

no synchronization

exit-address-family

Hope this helps.

Please rate any helpful posts.

[CiscoBrownBelt]

This is awesome!

Exactly how do you come up with the RD numbers such as 1:1 meaning what do they represent?

As for address-family ipv4 vrf VRF100 and BGP configs, are you saying to advertise the VRFs in BGP and similarly enforce policy address-family ipv4?

What about using EIGRP?

[omz]

I don't think this can be done purely using EIGRP/OSPF. RD and RT are BGP concepts.

Good posts to read with regards to RD and RT - 

http://packetlife.net/blog/2013/jun/10/route-distinguishers-and-route-targets/

https://www.rogerperkin.co.uk/ccie/mpls/route-distinguisher-vs-route-target/

EIGRP Inter-VRF Redistribution - 

https://community.cisco.com/t5/network-architecture-documents/eigrp-inter-vrf-redistribution/ta-p/3136798

[CiscoBrownBelt]

Awesome I will check it out thanks!