Security Incidents mailing list archives

Re: PIX Question


From: Shawn Davenport <shawn.davenport () CURRENEX COM>
Date: Tue, 31 Oct 2000 15:23:25 -0800

It refers to the IP Options field of the IP header. The field is 40bytes max
in length. 14 is listed as experimental access control on
http://www.isi.edu/in-notes/iana/assignments/ip-parameters . For the most
part options are very rarely used and I would be cautious of packets coming
in using ANY options!

In regards to the possibility of someone trying to mapping your network, I
would say the chances are good. Some of the more interesting IP options such
as lose and strict source routing can help provide a wealth of information
regarding network topology.

Hope that help!

Shawn


-----Original Message-----
From: Miller, Dan [mailto:dmiller () MICROTHERAPEUTICS COM]
Sent: Tuesday, October 31, 2000 11:05 AM
To: INCIDENTS () SECURITYFOCUS COM
Subject: PIX Question

I  am a 'newbie' to Security and have been a voyeur to this list-server
for a while - plus the 'education' - so please be gentle...

Recently the following message has been picked up at our PIX firewall:

     106012:Deny IP from 0.0.0.0 to 161.58.250.155, IP options: "0x14"

My question is what is an 'IP Option 0x14' ?

Just from the outside IP address I assume this to be some kind of
attempt to map or penetrate the network perimeter...
Any other opinions?

Thank you in advance.
Daniel Miller
IT Manager
Micro Therapeutics, Inc.


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