>A networking instructor on campus generously showed his students how to >send mail from spoofed addresses from within our system.
... as if they didn't know already ?? :)) >Told them not to do it ... tilting at windmills. >, but of course they are. (Honestly though, some of them would >have figured it out for themselves.) aw, you must be kidding!! :)) >I am set to relay only for two specific subnets on our campus. good >Other >security items checked are "Auto-deny possible hack attempts" and >"Disable SMTP VRFY command". Everything else is unchecked. ok >Is there a way to verify local addresses only no, with "relay for addresses", authentication for relay is by allowed ip address, nothing else. The "mail from: @senderdomain" is open season for the jokers. Have you gotten any mail from Osama or sheriff shrub, yet? :)) >and still accept outside >incoming mail? What might be my best options? There's nothing in Imail that combines "relay for addresses" AND ONLY IF "mail from: sender@Imaildomain". You could use "relay for local users" to force a @senderlocalmailhost, but then you are an open relay for spoofers from Internet. If you used "no mail relay" then everybody would have to use SMTP AUTH, but even then, Imail doesn't require the authenticated used to use a @senderdomain that is a valid IMail host. but at least you could trace in IMail log who was spoofing the @senderdomain. Len http://MenAndMice.com/DNS-training http://BIND8NT.MEIway.com : ISC BIND 8.2.4 for NT4 & W2K http://IMGate.MEIway.com : Build free, hi-perf, anti-abuse mail gateways Please visit http://www.ipswitch.com/support/mailing-lists.html to be removed from this list. An Archive of this list is available at: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/
