How to unblock port 25 traffic on AT&T U-verse

Sunday, October 9, 2011
It's simple, really.  Just call them! 

The technical support phone number for AT&T Uverse is (800)288-2020.  When the automated attendant answers, give your Uverse account number and ask for "Agent" until you get a real live human being.  I simply told them that I'm an AT&T U-verse customer and I would like to have port 25 unblocked.  They had to transfer me to Tier 2 support, which took just a minute, and then they immediately unblocked it.  Kudos to AT&T for the quick an easy resolution on a Sunday morning.

It's common for ISPs to block SMTP port 25 traffic from their DSL, cable, and other high-speed networks.  Most customers would never need to allow outbound port 25 traffic, and blocking it prevents all sorts of malware from propagating.  For those of us who run networks from home, it's great that AT&T can quickly and easily remove this block with no questions asked.

Be aware, however, that some block lists include the IP subnets associated with DSL, Uverse, cable, and other highspeed networks.  They do this with the errant idea that no one should be legitimately be sending SMTP traffic from these networks.  For this reason, I configure Exchange to smarthost my emails to the AT&T SMTP servers for ultimate delivery.  In my case, I asked AT&T to unblock TCP port 25 so I could configure Domain Secure connectors.


  1. Unfortunately it's not that simple anymore. ATT now wants to sell you a subscription to a "Connect Tech" service for $15/month to unblock it. Or a one-time charge of $49. The first agent I spoke with was in an India call center and declared "Tech 2 support can't fix this problem". She then transferred me to a barely understandable Phillippines call center to sell me the service contract. I declined.

  2. I would hang up and call back. Often times you get a different answer from a different agent. You may also want to point them to this blog article.

  3. One trick that you may consider is to call back a few times and if you don't reach a USA based call center, hang up and call again. After 3 calls within a certain time frame, I believe its 7 days or so, you'll be forwarded to the "VIP team."

    I had this happen to me after I had a 3 week nightmare getting my internet setup. I spoke to about 10 reps and finally hit the VIP team. He figured it all out for me.

  4. Thank you so much!!! I have been plagued with trying to solve this problem for so long I won't say [too embarassing]. Called. Asked for agent. Got through to a tier 2 tech [Scott] and he unblocked it pronto! No charge either. I share this not to show off in the leasst but help others of you out that that were pulling your hair out of this iss.

  5. The fact that people have to jump through all these hoops just to get a simple port opened up is simply ridiculous. AT&T Uverse rep clearly stated that there were no restrictions to internet services when I signed up. Now they say I have to pay for a service that I should already have. Not at all acceptable in my book. With that, I am switching over to Wide Open West as an alternative.

  6. Just called ConnecTech and they were useless before I could ask for port 25 to be open they wanted $49 to subscribe to their service. Looks like it is time to go back to cable internet.


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