nanog mailing list archives
Re: SPF Configurations
From: Tony Finch <dot () dotat at>
Date: Tue, 8 Dec 2009 16:39:07 +0000
On Tue, 8 Dec 2009, Suresh Ramasubramanian wrote:
As for a university smarthost getting blocked you'd probably need to look at one of two things -
Three :-)
1. Forwarding users on your campus - with mailboxes that accept a lot of spam and then forward it over to student / alumni AOL, Comcast, Yahoo etc accounts 2. Spam generated by infected PCs / laptops, hacked machines etc on your campus LAN
3. Spammers abusing your webmail and/or remote message submission service using phished credentials. If your incoming spam blocks are effective then forwarding shouldn't be too much of a problem. For on-campus bots, block port 25 and ensure your MX servers can't be used as outgoing relays (i.e. put your outgoing relay service on a separate address). If you are lucky your colleagues chose a really obscure name (not mail.* or smtp.* etc.) for your outgoing relay service 20 years ago so spammers are less likely to guess it :-) To protect against phished accounts, apply rate-limits to outgoing email. If you have good on-campus security hygeine then you can be much less strict about the limits for on-campus connections. Tony. -- f.anthony.n.finch <dot () dotat at> http://dotat.at/ GERMAN BIGHT HUMBER: SOUTHWEST 5 TO 7. MODERATE OR ROUGH. SQUALLY SHOWERS. MODERATE OR GOOD.
Current thread:
- Re: AW: SPF Configurations, (continued)
- Re: AW: SPF Configurations John R. Levine (Dec 04)
- AW: AW: SPF Configurations Andre Engel (Dec 05)
- Re: SPF Configurations Lars Eggert (Dec 04)
- Re: SPF Configurations Sean Donelan (Dec 06)
- Re: SPF Configurations Bill Stewart (Dec 06)
- Re: SPF Configurations Sean Donelan (Dec 07)
- Re: Official Mail, was SPF Configurations John Levine (Dec 07)
- Re: SPF Configurations Michael Holstein (Dec 07)
- Re: SPF Configurations Douglas Otis (Dec 07)
- Re: SPF Configurations Suresh Ramasubramanian (Dec 07)
- Re: SPF Configurations Tony Finch (Dec 08)
- Re: SPF Configurations Suresh Ramasubramanian (Dec 08)
- Re: SPF Configurations Michael Holstein (Dec 08)
- Re: SPF Configurations Tony Finch (Dec 08)
- RE: SPF Configurations Jeffrey Negro (Dec 04)