RE: Took network down with wrong access-list

From: Nate Kleven (cciemail@intellinet.ws)
Date: Thu Nov 14 2002 - 19:51:48 GMT-3


There is an implicit DENY statement at the end of all access-lists. With
that in mind, without any permit statements, all traffic was being dropped.
Try something like this:

Access-list 100 deny icmp any host 172.16.1.10 echo
Access-list 100 permit ip any any

Also, I noticed in your email that you mentioned this is on an Internet
router? The host 172.16.1.10 should not be reachable from the internet
anyway! Are you doing a static nat translation? If that is the case, your
deny statement should be for the public IP address, not the private.

HTH

__________

Nate Kleven

Senior Network Engineer, CCNP Voice Access, MCSE

Expanets

6020 So 190th ST

Kent, WA 98032

(206)219.6135

"Experienced at Networked Solutions"

-----Original Message-----
From: Jeongwoo Park [mailto:jpark@wams.com]
Sent: Thursday, November 14, 2002 2:03 PM
To: 'ccielab@groupstudy.com'
Subject: Took network down with wrong access-list

Hi all.
I like to share what I did this morning to take an internet connection down
for one of customers' companies.
 
Internet_router#
 
Interface s0
Ip access-group 100 in
.
.
.
access-list 100 deny icmp any host 172.16.1.10 echo
 
 
I was tring to set up access-list in a way that no one can ping one of their
servers in their network. This config took their internet connection down. I
immediately removed it, and it came back normal.
 
What did I wrong?
 
Thanks,
 
JP



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