But, AFAIK, Imail can not be configured to accept/listen on port 25 for all SMTP traffic AND accept/listen on port 587 for only authenticated traffic, i.e. no relay.
John Tolmachoff Engineer/Consultant/Owner eServices For You > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:IMail_Forum- > [EMAIL PROTECTED] On Behalf Of R. Scott Perry > Sent: Monday, August 02, 2004 11:29 AM > To: [EMAIL PROTECTED] > Subject: Re: [IMail Forum] BellSouth now blocking port 25 > > > >I wonder how long before ISPs start blocking 587. Certainly it doesn't > >take much for spammers to switch to 587 as well. > > There is a reason why an RFC defined port 587 when port 25 already existed. :) > > Port 25 is used for any SMTP connections -- from MUA (mail client) to MTA > (mail server) and MTA to MTA. Many ISPs now block outgoing connection to > port 25 since their customers should not be sending out E-mail directly to > other mailservers (as that is how spammers operate), and it is impossible > to distinguish MUA->MTA traffic from MTA->MTA traffic. > > However, port 587 traffic is *only* used for MTA->MTA traffic. For > example, if @example.com has an MX record pointing to a host that resovles > to 192.0.2.25, that IP is required to accept mail on port 25. If it also > accepts E-mail on port 587, it should only accept E-mail from authenticated > users. If it accepts E-mail from non-authenticated users (I haven't heard > of it happening yet), it will almost certainly get blacklisted. So ISPs > have no need to block port 587 traffic. > > -Scott > --- > Declude JunkMail: The advanced anti-spam solution for IMail mailservers > since 2000. > Declude Virus: Ultra reliable virus detection and the leader in mailserver > vulnerability detection. > Find out what you've been missing: Ask for a free 30-day evaluation. > > --- > [This E-mail was scanned for viruses by Declude Virus (http://www.declude.com)] > > > To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html > List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ > Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/ To Unsubscribe: http://www.ipswitch.com/support/mailing-lists.html List Archive: http://www.mail-archive.com/imail_forum%40list.ipswitch.com/ Knowledge Base/FAQ: http://www.ipswitch.com/support/IMail/
