Solved

Cisco FWSM Denying Outbound ICMP (type 3)

Posted on 2009-05-05
1
1,022 Views
Last Modified: 2012-05-06
I have a Cisco firewall that is logging the following SYSLOG (about 15 per second):

Denied ICMP type=3, from laddr 10.1.72.30 on interface Inside539 to 67.128.185.202: no matching session

The destination IP of 67.128.185.202 varies, but the source is always the same.  I have found that the customer has SolarWinds installed on this host.  Why would the firewall be blocking OUTBOUND packets when I have an outbound ACL (applied to Inside539 interface)?

access-list Inside539_access_in extended permit ip 10.1.72.0 255.255.255.0 any
0
Comment
Question by:Venyu
1 Comment
 
LVL 32

Accepted Solution

by:
harbor235 earned 500 total points
ID: 24314364


is someone scanning from inside your network outbound? Aah solarwinds, someone is scanning

ICMP type 3 is destination unreachable, do you have a default route outbound, can you route to 67.128.185.202 (try pinging from the same subnet) 15 per second is a pretty good rate.

The firewall will approximate icmp connections, if the icmp message does not have a nmatching component you can get this message, i am not sure how someone generates the type 3 unsolicitated unless they have a packet generator.

Coupls of things, sniff the traffic coming from the suspected port and see ehats coming in and going out

harbor235 ;}
0

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

I recently had the displeasure of buying a new firewall at one of the buildings I play Sys Admin at. I had to get a better firewall than the cheap one that I had there since I was reconnecting the main office to the satellite office via point-to-poi…
Network traffic routing plays key role in your network, if you have single site with heavy browsing or multiple sites, replicating important application data from your Primary Default Gateway ,you have to route your other network traffic from your p…
Email security requires an ever evolving service that stays up to date with counter-evolving threats. The Email Laundry perform Research and Development to ensure their email security service evolves faster than cyber criminals. We apply our Threat…

820 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question