Great Circle Associates Firewalls
(January 1995)
 

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Subject: various ident bits
From: Christopher Davis <ckd @ loiosh . kei . com>
Date: Tue, 31 Jan 1995 22:44:23 -0500
To: firewalls @ greatcircle . com

[This is not in response to any one message, but is just to clarify a
couple things that have come up in the various threads.]

- pidentd 2.5 can DES-encrypt the returned cookie so it's useless to the
  other end *unless he gives it to you*.

  Obviously if the attacker breaks root on your machine and stomps on your
  identd this is no better, but if they get into your machine as a regular
  user, then use your machine as a staging point, you'll have a useful,
  time & date-stamped log entry when you decrypt the cookie you got from
  the target's sysadmin.

  So no exposure of your usernames, but you still get some degree of
  after-the-fact additional logging.  Sounds like a win to me.

- Some PC TCP/IP stacks lose.  If there's nothing listening on a port,
  they should refuse the connection with RST, not stupidly suck up packets
  and wait for the other end to time out.  MacTCP gets this right ;-)

  This is not ident's problem, or sendmail's, or tcpwrappers.  This is a
  TCP/IP stack that doesn't follow the spec.  It's BROKEN.

Now, this is not to say that ident is for you.  However, a couple of
common reasons given for not running it are at least mildly debunked :)
-- 
 Christopher Davis * <ckd @
 kei .
 com> | "It's 106 ms to Chicago, we've got a full
 http://www.kei.com/homepages/ckd/ |  disk of GIFs, half a meg of hypertext,
   * MIME * PGP * WWW * [CKD1] *   |  it's dark, and we're wearing sunglasses."
Save swap space: gzip /proc/[0-9]* | "Click it." -- <bluesbros @
 bluesbros .
 com>

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