Inbound on port 25? I know my ISP does

Mine doesn't (Roadrunner). I run my own SMTP server off my cable modem. I have no problems getting incoming mail. Outgoing, however, was a pain because so many SMTP servers block mail coming from dynamic IPs. It annoys me to no end. I understand the reasons for doing it, but it annoys me to no end. I had to set up a small satellite server on a static IP that I route all my outgoing mail through.

This leads me to wonder why you run any portion of your mail server from your home if you have access to a small satellite server?

To search your home, a warrant is needed. To search a remote site, less is needed, and you might never know it’s been searched, back-doored and compromised.

Mostly because the small satellite server requires very little storage, cpu, or memory. I have about 100G of mail on my IMAP server (not all in one account: I run email for everyone in my family), and that kind of space isn't cheap in the server rental business (despite the fact that a 2TB drive is $90).

Plus I just like having my data here, and not somewhere where I have no physical access.

Come to think of it, I've never looked at inbound stuff. You'd think outbound would be where all the spam problems come from, though.

> You'd think outbound would be where all the spam problems come from, though.

They block port 25 to prevent open relays on their network (i.e. someone sends a forged email, the SMTP server does no authentication, and just forwards it on to the destination).

If you block 25 outbound, people's mail clients (Outlook, Thunderbird, etc) could not deliver mail to servers that don't run SSL or TLS (465, 587)

Lots of ISPs does this. They require you to relay via their SMTP-server.

Ideally you would use port 587, which is the designated port for mail submission. See RFC 2476 [1].

This requires that your mail provider supports that port, of course, which is unfortunately not always the case.

[1] http://www.ietf.org/rfc/rfc2476.txt

Used to have Bellsouth DSL, and they did this. SMTP/TLS on a different port worked though. But obviously you couldn't run your own e-mail server.