Yes, I knew this day would come that I too have my own rant about this ISP. For the record, I wasn't really able to choose a different ISP, as I they don't serve ADSL in this area and Comcast seems to be the only cable provider around. There's Roadrunner Internet and they have the cooler logo but they just offered a Comcast resale package, which is not really what I was looking for. And for another record I have to say that Comcast is pretty stable, I only have to reset the modem every other month or so - which is totally acceptable for a low-cost homeuser contract, IMHO.

That being said, I'm not too happy with Comcast's approach to net neutrality or just content mangling in general. IOW: Keep your hands off my traffic! Two major annoyances so far and the reason for this blogentry:

The so-called Domain Helper Service one has to opt-out to get useful DNS error messages

Apparently Comcast is blocking port 25. Of course, no one would ever send email from a MUA these days, with all the webmailers out there, right? One has to use port 587 to do SMTP via MSA. They even have a support page for this one (which can only be accessed when you turn off (!) JavaScript in your non-InternetExplorer browser). Maybe I should open a ticket with them and see if they can unblock ports on a per-customer basis. Hah!

I found the FAQ entry on which ports they're blocking, saying:

Ports 68, 135-139, 445, 520, 1080 are blocked by default.

Port 25 is not blocked by default but on-demand: "When spam from a compromised computer is detected, Comcast’s anti-spam systems automatically apply a sending block and send an email notification to the affected subscriber’s comcast.net email address." I don't remember any notification mail though....