RE: Sidewinder G2

["Perrymon, Josh L." <PerrymonJ () bek com>]

So the pix allows the 7 command in RFC 821 section 4.5.1--
DATA
HELO
MAIL
NOOP
QUIT
RCPT
RSET

If a remote client sends ESMTP it converts it to a NOOP command and sends it
to the firewall...
And it also analyses the data payload and if it finds an invalid request it
will remove the command 
or send a NOOP to the server.

The PIX will respond with xxxx's in the SMTP version if you do a telnet...

So it's a packet filter with application inspection...  right..??


-----Original Message-----
From: Valdis.Kletnieks () vt edu [mailto:Valdis.Kletnieks () vt edu]
Sent: Tuesday, November 18, 2003 10:20 AM
To: Perrymon, Josh L.
Cc: full-disclosure () lists netsys com
Subject: Re: [Full-disclosure] Sidewinder G2 


On Tue, 18 Nov 2003 09:49:52 CST, "Perrymon, Josh L." said:
> The cisco PIX doesn't run the actual SMTP service. The problem would be in
> the Fixup for the SMTP protocol.

Hmm.. so we *don't* actually do SMTP, we merely screw with the bits in
passing
even more than an actual SMTP relay would do (as it would just slap on a
Received: and keep going).  It answers a SYN packet on port 25, it sends a
distinctive '220 hello' reply different than what might be behind it, it
accepts EHLO/MAIL FROM/RCPT TO/DATA/QUIT, it isn't merely tunneling packets
to
a server behind the firewall.

Pedantic sophistry at its best.  It's an SMTP server, guys. Looks like a
duck,
quacks like a duck, and slapping a "this is a Fixup not a Server" label on
it
isn't gonna remove the duck feathers.

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