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Subject: Re: IMAIL (Ipswitch) DoS with Eudora (Qualcomm)
From: Anthony Santen (anthonySANTEN.NET)
Date: Tue Apr 04 2000 - 23:25:20 CDT

Ipswitch blames BOTH NetScape AND Eudora for not following RFC's, but does
nothing to control the situation.

It is very simple to deny service to any IMAIL 5.xx or 6.xx server as
follows.

IMAIL allows SMTP AUTH using various methods, including CRAM-MD5 and LOGIN
If a Eudora 4.3 client attaches to the IMAIL server supporting SMTP AUTH, it
attempts a connection using CRAM-MD5. At this point the mail server locks
the internal security dll (imailsec.dll) using 'Exclusive' mode, thus
disallowing other threads to access it. The session with Eudora 4.3 will
stay in a 'locked' state. Eudora doesn't disconnect or time-out, nor does
Imail.

While the lock is in place, NO mail client can use the server for outbound
mail

This problem has been confirmed to be only with Eudora at this time. Eudora
4.3 has been confirmed not to show this behaviour on MS-EXCHANGE or Sendmail
8.10.

The only 'work around' available at this time is to restart the IMAIL
services on the server.

Ipswitch's 'work around' is to open the relay, disabling the SMTP AUTH in
the process.

Ipswitch denies that the problem is theirs, and claims that 'everyone else
is mad but not us'. Several complaints regarding this problem have been
received on the IMAIL forum.

Anthony Santen