On Tue, 20 Nov 2012 12:29:00 +0000 Jason Ede wrote: > However, ISP's blocking smtp ports for suspected spammers would > help... Ideally they'd block all traffic on port 25 or 587 not sent > through their SMTP engine which would do some basic spam checks...
They shouldn't (and typically don't) block 587 (or 465), since that's used for mail submission to third-party ESPs. It's in no-ones interest to block that.
