On or near 11/6/03 7:11 AM, Remo Del Bello at [EMAIL PROTECTED] observed: > On 11/5/03 4:49 PM, Allen Watson deftly typed out: > >> David's suggestion is an excellent one, but I ran into an added problem when >> I tried it. My ISP, Earthlink, no only prevents me from using SMTP servers >> outside their domain; when I am connected to the Internet through them, I >> cannot use the SMTP server on my Mac!! On the other hand, I've corresponded >> with people who are doing this regularly, and report that they give >> themselves much speedier service than their ISP would. > > There are two methods employed by ISPs for controlling what mail traffic > leaves their network: > > - blocking mail with a return path that doesn't match the ISPs domain > (i.e. A message with a From: containing an Earthlink email account while > connected to the Internet through Verizon) > - blocking TCP and UDP traffic on port 25 > > In the first case you are only allowed to send mail through the ISP's mail > servers if the From address matches the ISPs domain. I believe Verizon, at > least in my area, does this. In the second case, port 25 is the port SMTP > traffic usually travels through, so, by blocking it, the ISP is trying to > ensure that all mail sending goes through their mail server (so that they > have a record of it and can track it). Both of these are measures they take > to control/restrict the spam coming out of their networks. > > If your ISP only does the first (return-path verification), you *can* send > mail...you just have to select an account that belongs to the ISP to send > with. If your ISP does port 25 blocking, then using an external SMTP server > or running a mail server on your machine will avail you nothing since that > mail server will try to communicate with others via port 25 and will get > blocked. > What seems odd to me is that, when I set up postfix and set 127.0.0.1 as my outgoing mail server, the message DOES go out. It just never comes back (and I am sending it to myself).
Is that consistent with the scenario where port 25 is blocked? Wouldn't I get an error message, as I do when I try using port 2025? (I realize it is highly unlikely that Earthlink has 2025 enabled, but I used that just as a test to see what a blocked port would return.) And, if port 25 is not blocked, then why is the message being "sent" but never received? Any ideas? > In my case, since I control the mail server at the company I work for, I've > added an additional SMTP listener on our mail server at port 2025 and > configured my accounts to send via that custom port. This way I can connect > to it from anywhere, whether the ISP is blocking port 25 or not. > > -Remo Del Bello -- Microsoft MVP for Entourage/OE/Word (MVPs are volunteers) Allen Watson <[EMAIL PROTECTED]> Entourage FAQ site: <http://www.entourage.mvps.org/> AppleScripts for Outlook Express and Entourage: <http://members.thinkaccess.net/[EMAIL PROTECTED]/Scripts/> Entourage Help Pages: <http://www.entourage.mvps.org/> -- To unsubscribe: <mailto:[EMAIL PROTECTED]> archives: <http://www.mail-archive.com/entourage-talk%40lists.letterrip.com/> old-archive: <http://www.mail-archive.com/entourage-talk%40lists.boingo.com/>
