>> Mcaffee Webshield SMTP, on evaluation the best product for us, but now
has
>> some problems if you use it heavily.
> "some problems" like what?
> It stops working completely and blocks your mail flow?
> It works but too slowly, with the mail queue getting too long?
My opinion is biased, but I thought I would comment on this.
I installed WebShield SMTP at a site that was running IMail and needed virus
protection. The first problem occurred when an large E-mail (3 megabytes,
IIRC) was sent to 50 people. The first recipient's mail server was down,
and WebShield SMTP ended up sending the message to all 50 people each time
it couldn't reach the first recipient. It wasted about 150 megabytes of
bandwidth, and annoyed a number of potential customers of the company.
Another problem is that it can't be set up properly for anti-relay (like
most SMTP-based virus scanners). It allows you to restrict relaying to
certain IPs, but you can't then use SMTP authentication for others. So,
anyone not on your set of IP addresses who has to send mail gets to send out
viruses.
Another problem is that anyone can launch a DOS attack by sending E-mail
addressed to [EMAIL PROTECTED] (note the "." at the end). When you
do that, the mail keeps getting sent back to the machine (adding a
"Received:" header each time) until the server slows to a crawl. Since I
was stupid enough to come up with a workaround (having "yourdomain.com." as
an alias to "yourdomain.com") when I submitted this to BugTraq, NAI/McAfee
decided it wasn't worth fixing this security hole.
There are a number of other (mostly minor) "gotchas" that keep popping up.
For example, it doesn't record the IP address of the remote SMTP connection
in the Received: field yet.
But, the advantages of having most mail scanned for viruses can outweigh the
nuisances that can come up.
-Scott
Declude: Anti-spam and Anti-virus solutions for IMail.
http://www.declude.com
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