Tony Varriale wrote:
Any chance you could give the group more details before saying it can't be trusted?

I'm afraid I don't have any concrete details to add, but I've found capture expressions on Firewall Service Modules to be quite inconsistent. Presumably this is something to do with the modules interaction with the chassis? I haven't had the time to lab this, and I haven't always had problems, but I now generally work to the mantra that "the absence of a packet in an FWSM capture is not proof that the packet does not exist, but the presence of a packet in a capture does prove it's existence".

Perhaps there is a cisco documentation on this, listing known caveats and limitations?

Sam

tv
----- Original Message ----- From: "Higham, Josh" <[EMAIL PROTECTED]>
To: <cisco-nsp@puck.nether.net>
Sent: Monday, June 30, 2008 10:41 AM
Subject: Re: [c-nsp] Telnet FROM a PIX Appliance?


[mailto:[EMAIL PROTECTED] On Behalf Of Ziv Leyes

I guess it's more as a "working right" educational purpose,
so you won't use your firewall as a debugging client.
In newer versions there's the packet tracker that can help
you debug connectivity problems.
Ziv

As an FYI, the ASA/Pix packet capture cannot currently be completely
trusted (version 8.0).  I found an annoying bug where I would capture
the frame on a span session monitoring the port connected to the
firewall, but it wouldn't show up on the firewall capture.

The packet in question was also being dropped by the firewall, but with
no logging (and with a permit ip any any rule in place).  The 'fix' was
to apply a nat translation and then remove it.  TAC was completely
unhelpful (worst ever TAC experience).

Blocking outbound sessions on the firewall also means that it can't be
used to bounce an attack, if compromised.

Thanks,
Josh


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