said by NormanS :

A low volume MTA on a residential connection is less strain on network capacity than P2P file transfers.

The way the TOS is written appears to restrict running a server for other than personal use.

Addendum:
But there is still the fact that the way it is written gives leeway to Comcast to act against their users, if they desire. I have just never heard of a TOS action for running a server. Comcast has sent letters to people who have exceeded some threshold of outbound SMTP traffic (regardless of whether they were running servers, or not), and high bandwidth usage (the only ones reporting that letter were running P2P, not mail servers).

said by bigchris :

Well there's always the TOS to consider..

said by Hehe :

They said I was sending spam. I was only forwarding a copy of all email I received to my gmail account.

said by funchords :

An open port 25 has zero to do with sending spam. Open ports are for receiving connections.

You MAY have had an open relay.

said by funchords :

Running a PRIVATE MAIL SERVER does not violate the TOS.

said by Hehe :

Comcast cut-off my service.
I called and was directed to their security group.
I was told if they ever detect port 25 open again they will cut-off my service forever.
They said I was sending spam. I was only forwarding a copy of all email I received to my gmail account.

My firewall prevents all outbound to port 25 except from my email server.
I no longer have an email server?

My email server is only used for personal email, no business.

said by Hehe :

Comcast cut-off my service.
I called and was directed to their security group.
I was told if they ever detect port 25 open again they will cut-off my service forever.
They said I was sending spam. I was only forwarding a copy of all email I received to my gmail account.
My firewall prevents all outbound to port 25 except from my email server.
I no longer have an email server?
My email server is only used for personal email, no business.

I would switch to FIOS if they allowed ports 25 and 53. 80 would be nice.

said by Guestin94087 :

Since you were forwarding all your mail (some of which included spam) to gmail from other sources, Google (gmail) caught that spam and identified your comcast IP as the sender. They probably notified Comcast that one of Comcast's machines was being used to send spam, and Comcast stopped you. You do not need an open relay to fall into this trap...mail forwarding is not as innocent as it seems.

I've seen small hosting companies having a hard time with email services such as Yahoo Mail and Gmail because their users forward catchall accounts to those services. Then the services, which have users clicking "this is spam", blacklist the 'offending' IP's of the hosting companies, so none of their users can send mail to anyone at those services until they go through hoops to get off the blacklists (the lucky ones get on a whitelist, but it's hard). They aren't the original senders of the spam, but the email services consider forwarding spam just as heinous an offense as originating spam.

said by NormanS :

Then port 25 was not open. You were using outbound port 25 to send email, not inbound port 25 to receive email. Not the same thing as "running a server".
Outbound port 25 is used by clients, not servers. Even though it is a component of my mail server, the "Mercury SMTP Relay Client", which connects to my ISP Message Submission Server, is just what its name says, a "Client". (And it isn't using port 25, either!)
I will reiterate:

quote:

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Comcast has sent letters to people who have exceeded some threshold of outbound SMTP traffic (regardless of whether they were running servers, or not)...

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Getting cut off for exceeding the threshold of outbound SMTP traffic is what Comcast is notifying people about. It looks, to them, like you have been infected with a spamming 'bot. Not the same issue as inbound SMTP traffic.

I have never heard of Comcast notifying people of abuse for inbound port 25 traffic. Your notice is not the first.

said by justbits :

It sounds like you're accepting mail on port 25 and forwarding it to Gmail on port 25. If you accept incoming email on port 25, then forward it using encryption and authentication to gmail on port 587, Comcast won't be able to look at your forwarded email and they wont be able to identify what you're doing.