From: Brian Dennis (bdennis@internetworkexpert.com)
Date: Tue Jul 31 2007 - 16:12:59 ART
If you ping yourself the ICMP echo is being transmitted onto the
Ethernet network. Then when you try to receive the ICMP echo that
you sent your inbound ACL is denying it. When pinging yourself you
are the sending an ICMP echo, receiving an ICMP echo, sending an ICMP
echo reply and finally receiving the ICMP echo reply.
Brian Dennis, CCIE4 #2210 (R&S/ISP-Dial/Security/SP)
bdennis@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Direct: 775-745-6404 (Outside the US and Canada)
On Jul 31, 2007, at 11:20 AM, NITIN NITIN wrote:
> Hi Experts,
> I have these ACL applied on int and cant ping my own ip why ?????
> although inbound icmp echo is denied ....... icmp echo-reply is
> permit
>
> Rack1R4#sh access-lists R3-in
> Extended IP access list R3-in
> 10 deny icmp any any echo (48 matches)
> 20 permit ip any any (1946 matches)
> Rack1R4#sh access-lists R3-out
> Extended IP access list R3-out
> 10 deny icmp any any time-exceeded log
> 20 deny icmp any any port-unreachable log
> 30 permit ip any any
> Rack1R4#ping 204.12.1.254
> Type escape sequence to abort.
> Sending 5, 100-byte ICMP Echos to 204.12.1.254, timeout is 2 seconds:
> !!!!!
> Success rate is 100 percent (5/5), round-trip min/avg/max =
> 60/77/100 ms
> Rack1R4#ping 204.12.1.4
> Type escape sequence to abort.
> Sending 5, 100-byte ICMP Echos to 204.12.1.4, timeout is 2 seconds:
> .....
> Success rate is 0 percent (0/5)
> Rack1R4#sh access-lists R3-in
> Extended IP access list R3-in
> 10 deny icmp any any echo (53 matches)
> 20 permit ip any any (1981 matches)
> Regards
>
>
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