We have IronPorts rather than Barracuda(s) here. 4 of them (2 at each 
data center) sit at the border of the mail "cloud" and perform virus and 
spam scanning, connection throttling (or blocking) for problem 
servers/domains, quarantining/greylisting, and other assorted functions.

Since enough people are still worried about false positives for spam, 
they flag (suspected) spam mail so that individual users can set up 
their own filters, and drop/delete viruses. The 4 IronPorts are the only 
systems that are allowed to communicate with either the central mail 
system or the Listserv host.

Anything flagged as Spam-Positive is dropped by the MTA on the Listserv 
box. I saw both raw connection numbers and the load on the Listserv 
system drop by 50% when the current setup went into effect.

-Chris


John Kelley wrote:
> That and I use a spooling service that performs "partial" greylisting.  
> Those two things cut my spam by nearly 2/3's.  I also quarrantine 
> embedded and linked images and went through the process of whitelisting 
> people who typically post with them.  I also loaded into my whitelist 
> all the list admin email addresses, and whitelisted a couple of domains 
> that post a lot to many of the lists.  I can send you copies of my 
> blocks as well if you are interested.
> 
> John
> 
> At 12:36 PM 3/20/2007, you wrote:
>> We put the 'cuda at our border instead of just the Listserv server
>> itself and it greatly reduced the amount of spam that was being sent to
>> the lists from external.
>>
>>   Bob
>>
>> > -----Original Message-----
>> > From: LISTSERV site administrators' forum [mailto:LSTSRV-
>> > [log in to unmask]] On Behalf Of Anne Toal
>> > Sent: Tuesday, March 20, 2007 8:56 AM
>> > To: [log in to unmask]
>> > Subject: A Listserv behind a spam firewall
>> >
>> > We recently put up a Barracuda spam firewall and I would like to know
>> if
>> > anyone out there has compiled best practices for running a Listserv in
>> > that
>> > way.
>> >
>> > Yes, I know the Listserv has anti-spam protection. However on lists
>> that
>> > are
>> > set up to send all posts to a moderator, it appears to ignore whether
>> > the
>> > message is spam and it sends the message approval requests anyway. I
>> > would
>> > like to use the Barracuda to stop those as well.
>> >
>> > The Barracuda can suppress daily spam summary messages, so we wouldn't
>> > have
>> > to worry about a daily summary message going to the members of all the
>> > lists. It can also send the daily spam summary messages to a specific
>> > address. Does anyone have experience with either configuration? How
>> well
>> > did
>> > it work?
>> >
>> > Does anyone have any methods that don't involve using an external
>> > antispam
>> > firewall to stop these unwanted approval requests full of spam?
>> >
>> > -aht

-- 
Christopher Wilson
Information Systems Coordinator
ISS Enterprise Systems
The George Washington University
202-994-3878
[log in to unmask]