03-26-2002 11:54 AM - edited 03-01-2019 09:02 PM
I have two Cisco 2501 routers connected together by their serial interfaces(Lab-D via s0 and Lab-E via s1). Everything is working properly.
Now I configured an access-list on Lab-D denying any traffic that comes in from Lab-E's IP address.
Lab-D serial 0 = 214.16.4.1
Lab-E serial 1 = 214.16.4.2
On router Lab-D:
access-list 1 deny host 214.16.4.2
access-list 1 permit any
On int s0 of Lab-D:
ip access-group 1 in
---------
So, when trying to ping from Lab-E router to IP address 214.16.4.1, I get a U.U.U answer to my ping query... which is normal !
But, if I ping from that same Lab-E router to IP address 214.16.4.2, I also get the U.U.U answer... which does not sound too normal to me.
My question is: How can this happen? How is my Lab-E's serial interface from the router itself affected by Lab-D's access-list?
Thanks..
03-26-2002 11:58 AM
When you ping your own serial interface, the frames are actually sent on the wire and the remote router sends them back. Since you have a access on the remote router, the frames are not getting back.
03-26-2002 12:09 PM
Thanks alot. That explains everything. And a quick answer too.
Thanks!
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