US Telco Support → AT&T → AT&T DSL > Port 25 showing as closed

Port 25 showing as closed

I ran a scan from grc.com. Port 25 shows 'closed' instead of 'stealth'. Does anyone know why?

AT&T closes port 25 long before any data is sent via port 25 to your computer. This is done as an anti-malware / anti-spam action, since POP protocol uses port 25 as a default value. AT&T DSL uses ports 465 and 995 (SSL email ports) and not 25, so the blocking by AT&T of port 25 does not affect AT&T POP email.

This may be the reason that you see what you see.

Not to my knowledge. Someone else may have a resolution for you, but I'm afraid that I do not.

At various points in history, you could ask to have port 25 unblocked. I'm not sure that's still possible. At any rate, why do you care how the blocked port is answered?

To clear up the questions

1.) yes- AT&T blocks the following ports on residential accounts. Outbound - TCP port 25, Inbound and outbound - TCP ports 135, 139, 445 and 1025

2.) in the past and before 2008 if you had port 25 outbound enabled on AT&T you could request it be unblocked still. Past 2009, if you disconnected and reconnected that option went away. in 2010, irregardless of consumer status, all were blocked at that point. Bellsouth customers were apparently blocked since day 1 when it started for consumer. I believe in present day 2013, all consumer accounts that are new are blocked by default now with no option to remove it.

hopefully that clears a few things up. As most customer migrate to IMAP based email and web based email I suspect the POP and SMTP days will be numbered eventually to the point where people won't use them anymore and leave them "on the cloud".

Also in 2010-2011 timeframe AT&T stopped supporting client based email type of software (outlook, eudora, incredimail, thunderbird, etc..) and only support web based email now. If you can go to mail.yahoo.com and login with your userid and password that is the end of the scope of their support.
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At least one piece of AT&T CPE is actively listening on 3479: Pace 4111.

»2Wire 3801HGV - ports open (even when I didn't open it)

»Re: Pace 4111N
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Norman
~Oh Lord, why have you come
~To Konnyu, with the Lion and the Drum

Virtually all POP apps allow you to specify the send port. Just change it to 465 or 995
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I still haven't gotten a straight answer out of AT&T about SMTP port 25 INBOUND being blocked. That's a poor techsupport problem on AT&T's behalf, but that's the subject of another discussion entirely. I understand most ISPs have blocked OUTBOUND only for the past 10+ years and claiming on the grounds to prevent spamming botnets... OR perhaps it is to force you to become dependent on their email service? Hmmmm....?

Over the years I have worked for several webhosting companies and I have dealt many calls or helpdesk tickets each day as to why our "SMTP server was down" when in fact it was their ISP's imposed SMTP OUTBOUND firewall rules. Do you think the customer wants to be told that? Not one customer ever listened to me without an argument.

Then one day my mail caching server stopped receiving email... on SMTP INBOUND port 25, I had never heard of any ISP blocking INBOUND before then, and getting them to answer that was impossible, nor was there anything on the website about it.

Anyway, I am glad that this thread answers the question that I have been asking them for years. Thanks guys!