GRE tunnel protocol status goes down with vrf membership

[kaustav.gupta]

I have setup of 4 routers R1 - R2 - R3 - R4 .

They are connected as shown. I have also setup a GRE tunnel between R1 and R4. The tunnel status is up and protocol is up.

I have configured tunnel source and reach ability related configurations in R1,R2,R3 and R4.

Now if I put R1/R4 Tunnel Source Loopback Int, Tunnel Interface and Int connecting R2/R3 in vrf A and also modify the static route to reach Tunnel Destination IP in R4 into a vrf static route the tunnel protocol goes down.

Can anybody help ?

Thanks

Kas

[shivlu jain]

Hi

Tunnel protocol down means the destination is not reachable in vrf routing table.

Please check have you given the reverse route in vrf.

regards

shivlu jain

[kaustav.gupta]

Hi,

I have configured vrf static routes Tunnel source and desitination and tested xtended ping vrf A dest loop source int lo0. I got ICMP type 8 & 0 msgs which is absolutely fine. So source and destination loopbacks are reachable .thats probally not the issue .

[Cedric Smulkowski]

Hi all

Thanks a lot !! After 2 days on testing with GNS3, to find why the protocol int tunnel stay down and not showing up in the route table of this VRF, found your post, guys and it works !! On the web, found many example without this command. I have tried 2 scenario, and this command was not here. You made my days, can use this solution in my job, just in time. On top of that, i use DMVPN, and it works great. Thanks

Ex :

tunnel source 192.168.240.1
tunnel mode gre multipoint
tunnel vrf name_of_your_VRF

[Harold Ritter · Accepted solution]

Kas,

you need to configure "tunnel vrf " under the tunnel interface configuration to tell the tunnel interface that the tunnel destination is resolvable via the specific VRF. By default, the tunnel destination is resolvable via the global routing table.

Regards

[kaustav.gupta]

Hi,

But if I have configured a ip vrf forwarding A under the gre tunnel interface will not take care of it.

Anyways i am trying out your command

[Harold Ritter · Accepted solution]

Kas,

The fact of configuring the tunnel itself in a specific VRF, using the "ip vrf forwaring , doesn't force the IOS to perform the tunnel destination lookup in that VRF. The tunnel destination lookup is still performed against the global routing table by default. Only the "tunnel vrf" command can change the default behavior.

Regards

[AminRamadan]

I know this is old thread but we have to as following:

vrf destination vrf_name
address-family ipv4
exit
!
interface tunnel 0
vrf forwarding NAME 
tunnel vrf NAME
ip add Xx.x.x
tunnel source x.x.x.x
tunnel destination x.x.x.x
exit

[HossamEddineihab]

@Harold Ritter  Should be both exist because in case you gonna ping , the ping not success without " Ip vrf forwarding " , I tested in the LAB. to make two sites ping each other should interface tunnel as below example: 

interface Tunnel0
ip vrf forwarding ABC
ip address 100.0.0.1 255.255.255.252
tunnel source Ethernet0/1
tunnel destination 11.0.0.2
tunnel vrf ABC

[Harold Ritter]

Hi @HossamEddineihab ,

There is actually four possible combinations that could be used. The one being used depends on the specific use case.

1- The tunnel source and destination being resolved via the global rib and tunnel interface being part of the global. That is the default behaviour.

2- The tunnel source and destination being resolved via the global rib and the tunnel interface being part of a vrf other than the global rib.

interface Tunnel0
ip vrf forwarding ABC

3- The tunnel source and destination being resolved via a vrf other than the global rib and the tunnel interface being part of the global rib.

interface Tunnel0
tunnel vrf ABC

4- And finally, the case where the tunnel source and destination are resolved via a vrf other than the global and the tunnel interface is part of a vrf other than the global rib. This is the scenario you are referring to.

interface Tunnel0
ip vrf forwarding ABC
tunnel vrf ABC

Regards,