On Wed, 2010-07-21 at 10:02 +0100, Jonathan Tripathy wrote: > Port 25 outgoing will be blocked by most ISPs > ------------------------------------------------------------------ > > This may be the case in your country, but from where I'm from, I've > never had a problem sending out on port 25, even on home residental > ISPs :)
My observation is the same. I am aware of only one "ISP" blocking outbound port 25, and that is Three, and from what I have been able to check, they only block for access from mobile phones. Of course, outbound port 587 isn't blocked. Back to the original point about SSL DDoS, you have to consider how SSL works for SMTP. The correct way to do SMTP encryption is via TLS, not SMTPS, which mean the connection gets set up without SSL, and then switches to TLS on protocol level. That means the client would have to know how to talk SMTP first, which BT clients don't. OTOH, if you are running SMTPS, then SSL would get established first, before the protocol connection is set up, so you would get hit with the SSL setup overheads. But you shouldn't be running SMTPS, it's very existence is an ill thought out hangover from the dark ages. Gordan
