block outgoing attachments? 1

[chipk]

This ability doesn't seem to be native in Exchange 5.5. Has anyone ever figured out a way to do it? I've been looking at using Trend ScanMail's attachment blocking feature to do this, but that's an all or nothing, and I only want to block outgoing attachments going through my IMC.

 

[Griffyn]

All you need is to set up an SMTP server on your network that can handle attachment blocking. Then set up your IMC to forward all mail to your SMTP server, which would then do the attachment blocking, and then forward the mail out to the internet.

So, try searching around for any sort of solution that can do this for you. There may be some freeware linux distros set up, so don't exclude them. You can easily set up a linux install in a virtual machine. Check out VMWare Server (it's free) - it's pretty amazing if you've never used it before.

 

[chipk]

Yeah, that's what I was trying to avoid. I've set up Linux as a smart relay before, but hadn't thought of doing it on VMWARE, which I also use all the time. Thanks for that suggestion.

 

[chipk]

Ok, I actually got a working solution in place and figured I'd share the results. Anybody who has ever paid money for an e-mail antivirus, filtering, or security solution needs to check this stuff out. I've set up Linux servers with Sendmail before, but never delved as deeply into the AV and filtering solutions that are available. You can pay tens of thousands of dollars on solutions, or you can do it all for free. Amazing.

I set up Dell PowerEdge 2650 with CentOS (which installs on just about any hardware with no problem whatsoever); CentOS is basically Enterprise Red Hat Linux, minus the logo:

http://www.centos.org

(NOTE: The reason I used a whole server and not VMWARE as Griffyn suggested is because a) I ended up with several spares after a consolidation project, and b) I plan on using several other *NIX utilities on this server to get as much use out of it as I can - possibly MRTG, Snort, RADIUS or some others)

I configured Sendmail to use the MIMEDefang milter

http://www.mimedefang.org/

to strip out the attachments that I do not want to come through.

Then enabled relaying for all the domains I wanted to do forwarding for, and BLAMM-O! Working filtering solution for (practically) free.

 

[Griffyn]

Good stuff. Thanks for sharing.