Set EIGRP interfaces as passive

[jstrine]

I want to enable "passive-interface default" on my EIGRP config and specify certain interfaces as "no passive" (presently they are all active). However, when I issue the "passive-interface default" all my interfaces go passive and I must at that time "no passive" the ones I want to work. Doing this remotely causes neighbors to drop and I loose connectivity.

What is the best way to accomplish this change without causing loss of connectivity?

I'm thinking that a "merge" file with "copy tftp run" may be what I need to do.

Thoughts or recommendations?

[bvsnarayana03]

Dont know what will be the impact of that tftp show.

I would have configured each passive-interface separately. Later when a scheduled downtime is approved for the site, I would configure passive-interface default & later activate required interface.

[Kevin Dorrell]

It is always a problem when you need to do a change involving multiple config lines, and some of the config lines lock you out of the session. I have developed a technique that I have used successfully:

Make a small file with the configuration changes. You must make sure this file is correct! Then TFTP the file to flash with copy tftp flash, giving it a suitable name. Then do a copy flash run and pray that you got the commands right. This will merge the commands from the flash file with the current running configuration.

I think you will still lose the adjacencies briefly, but they should come back.

[Kevin Dorrell · Accepted solution]

OK, I tried out my scheme with the small configuration file in flash in my lab, and it worked fine. However, as I thought, it did temporarily lose the adjacencies between the passive-interface default and the no passive-interface commands. (I should mentioned that I had all my EIGRP timers trimed to the absolute minimum 'cos I was testing re-convergence at the time.) But it all came back OK.

Be aware that if you do it on a 2600, as I did, when you TFTP to flash it offers to erase the flash first, with a default of "Yes". Of course, you should say No!

Kevin Dorrell

Luxembourg

[shivlu jain]

if you do the following

no passive interface

passive-interface default

shivlu

[jstrine]

I can't verify this for sure, but I seem to recall that doing the commands in that order would not work. Basically the "passive-interface default" would remove any of your "no passive-interface " statements.

I'd have to try it in the lab to be 100% certain though.

[Kevin Dorrell]

That is correct.

[shivlu jain]

If it resolves the issue please rate me.

shivlu