Alternative to Port 25

[LuckyTaxi]

We're in the process of testing a mail server that we hope will replace our current one that's being hosted by our ISP. We learned a few things along the way and would like to avoid them if possible. The biggest hurdle is getting around port 25 (SMTP). Our work force is approx 75% consultants who work from clients' sites. Many of these places block port 25, therefore our users can't connect to send emails.

I know it varies from site to site depending on what their IT dept puts in place, but is there a range of port that's safe to use? I know comcast blocks port 25 but I read there's a workaround with using port 587 to get around this. For those who have dealt with this, what solution did you come up with?

 

[Jamsan]

We use port 587, as many home users have issues when they need to send mail and their 25 is blocked. No issues thus far - just make sure your mail provider supports connections on 587.

 

[RebateMonger]

If you use Outlook 2003/2007 and Exchange 2003/2007, you can send/receive email via TCP Port 80 with the "Outlook Anywhere" protocol (RPC over HTTPS). No ISP blocks outbound requests to Port 80.

Obviously, you could use a webmail client, too, again on TCP Port 80. Outlook Web Access if you use Exchange.

 

[Genx87]

Use RPC over HTTPs if you are runnning exchange.

 

[heymrdj]

Use the 587 port (secure port). If that doesn't work, then if you're using Exchange, as mentioned, use Outlook Anywhere. If you want a an opensource exchange that also installs an "Outlook Anywhere" kind of system (very very good), use Zimbra. If you're just installing an smtp and pop server on your server, then just use a webclient like squirrelmail so you can access via port 80.