US Cable Support > Comcast HSI > Comcast now blocking SMTP?

Comcast now blocking SMTP?

I just tested sending mail to my server at home and it was received just fine, so port 25 is working on my end. I am not in NJ though

Ok thanks I'll reboot by firewall maybe that will fix it.

It appears they are in Niles, IL(chicago)
I am trying to firgure things out. I called and they claimed port 25 was being routed to 587.

I can telnet smtp.comcast.net through 587 but not 25. However, it does not seem to the case in reverse. People coming into me through port 25 are not being redirected to my port 587.

Looks like I will be leaving comcast soon.

I am guessing they put some kind of block on me. I have not been able to find anyone else complaining. However it might be related to this recent port redirecting they have done.

What is odd that port 25 incoming is blocked. Last time they tried this crap, it was outbound. Even then, I could still reach port 25 at smtp.comcast.net. Their smtp gateway threw port 587 is asking for some kind of authentication. If I could get that to work it would be OK.... but INCOMING.. i repeat incoming is not working.

I am going to try tech support and spill the beans about my server. If that doesn't work, I found a website about getting your port 25 unblocked. However, funny thing is you have to email them. Lucky I have other email accounts.
»www.mailerblog.com/?p=19

reply to qhplar

Considering I have been using them since the AT&T craziness and the fact that we have been through this in 2004(mass port25 blocking) I can complain a little.

But you are right, it does violate ToS so I will see if the cancellation department can throw it's weight around, then I will try this mystery secure-port25@comcast.net email. If that doesn't work then I will be switching to DSL.

Too bad I like comcast. It was fast and despite being dynamic my IP never changed for years! Unlike some other companies which force you into a new IP every couple of hours.

reply to qhplar
I would fully support a block by all residential ISP's.

Hob

I like what they where doing. Which was having abusers/spammers/zombies being "flagged" and blocking them.

I am not even sure if outgoing port 25 is being blocked because for the past several years I have been relaying through smtp.comcast.net like a good little boy.

Why the hell is incoming being blocked! I can deal with not being able to send out email. Hell, I have several other servers that I good relay through if need be.

Blocking inbound port 25 is what is pissing me off.

Why would the AVERAGE residential customer need incoming port 25 open? What purpose does it serve Mrs Jones?

Hob

The average, I use the internet and like having comcast.net hotmail.com yahoo.com at the end of my email, user does not.

In fact the only people who need incoming port 25 are people like me.(there is no harm with allowing incoming)

However, outgoing is another matter. Some people connect to their work email and put in their outgoing email server as using port 25. This is what comcast is trying to change. They are forcing people to switch to the new(ish) standard of using port 587.

But instead of blocking just outgoing.... like they tried doing in the past, they are blocking all port 25s incoming and outgoing. This is a problem for a user like me.

I am still not sure if this is an isolated incident to myself or widespread. However port 25 seems to have stopped working at the beginning of the month, and when I called they already had a scripted response and would not escalate me to a higher tier. So I am under the assumption that this is or is going to be widespread.

I knew this day would come. The good thing of all this is that I will actually pay less for DSL(with a static IP). The bad thing is I lose my cable TV. Which might not be bad because we have been thinking to go full on cable box digital package anyway.

reply to hobgoblin

reply to qhplar
Comcast does selectively block certain users through a TB25 config file. It is possible, however, that they have begun blocking port 25 or entire segments of the network.

reply to qhplar
i would think they would block gaming ports, IE common steam ports and port 80 to keep the web servers down. the average computer user is not near savvy enough to be able to hook up an exchange server at their house.

please block all incoming SYNs. kthxbye.

reply to centran
Just use one of the many free/cheap external gateway options if you want to host your own mail server. (think redirection to a different delivery port)

I'm fully supportive of Comcast blocking port 25 because there are a multitude of options available for the clueful user to work around the restriction, and it should help to significantly reduce the amount of spam being spewed from Comcast's network.

-Eric

reply to hobgoblin

reply to centran

reply to espaeth