Pretty cool/unexpected behavior in IOS...

So I'm playing with distribute-lists today and decided to test how it worked
with redistribution.

I set up OSPF on one side and EIGRP the other and redistributed my EIGRP
routes into ospf.
I set up the distribute-list (#) out ospf 1 command to deny one of the 3
routes being redistributed
into ospf. Unfortunately, I couldn't get it to work and all of the EIGRP
routes were still redistributed
into OSPF.

Frustrated, I decided to replace OSPF with RIP. I did "no router ospf 1" on
all routers that had it
and then configured RIP on them. When I did a show run on the redistributon
router I noticed that
the IOS already converted my distribute-list out ospf command to
distribute-list out rip -ON IT'S OWN.
I went back and forth between replacing RIP with OSPF and OSPF with RIP and
every time the IOS
modified the distribute-list out (IGP) on its own. Weird thing is, when I
just removed the protocol,
(to where neither RIP or OSPF was present), the IOS removed the
distribute-list out (IGP) command
altogether.... but after 10 minutes, when I added RIP, there was the
distribute-list out command again
all on its own.

I scrolled through the buffer in secure-crt to get the old config:

Before:

router eigrp 1
 network 150.50.21.0 0.0.0.255
 distribute-list 10 out ospf 1
 no auto-summary

After:

router eigrp 1
 network 150.50.21.0 0.0.0.255
 distribute-list 10 out rip
 no auto-summary

Try it yourself....

Bryan R.

Blogs and organic groups at http://www.ccie.net
Received on Sat Apr 18 2009 - 16:23:47 ART