How can i pin outgoing interface ip address with RT and/or loopback int. ?

[bej]

This is my problem :

I have one management site and 3 other sites, site A,B and C. The management site is represented by one VRF and is located on the router(made up of 3 loopback addresses, no physical interfaces, the site is located on one of the routers participating in the mpls domain). The 3 sites are fully meshed to each other in a "simple" VPN topology.

The management site is used only to telnet the other sites so only one prefix will be advertised to each site. The following prefixes is advertised:

To site A: 1.1.1.1/32 RT 100:100 tag 19 (vrf NMC)

To site B: 2.2.2.2/32 RT 100:101 tag 20 (vrf NMC)

to site C: 3.3.3.3/32 RT 100:102 tag 21 (vrf NMC)

I have checked and confirmed that each prefix is installed in the approriate site. When doing this i can only telnet or ping site A and by doing a debug i found the source of the problem. The source address when sending a packet is prefix 1.1.1.1/32(First loopback interface, normally would have been outgoing physical interface) which only site A

has installed in its route table. I could easily have solved the connectivity problem by advertising prefix 1.1.1.1/32 to site B and C or by assigning the loopback interfaces to different VRF's. What i want to achieve is to pin the source address to a route target and a loopback interface so that when sending a packet to site B the source prefix is 2.2.2.2/32 and when sending to site C the source prefix is 3.3.3.3/32.

[Harold Ritter · Accepted solution]

Have you tried:

telnet /vrf NMC /source-interface lo1

telnet /vrf NMC /source-interface lo2

Hope this helps,

[bej]

Thank you. Is it possible to specify source interface when doing a ping or to change the source interface on a permanent basis ?

[Harold Ritter]

It is certainly possible when doing a ping:

r8#ping vrf NMC

Protocol [ip]:

Target IP address: 9.9.9.9

Repeat count [5]:

Datagram size [100]:

Timeout in seconds [2]:

Extended commands [n]: y

Source address or interface: 2.2.2.2

Unfortunately, I don't know of any way you could change the source address selection permanently based on which destination address the traffic is directed.

Hope this helps,