Did Verizon just shut down port 25?
wilddoktor
Newbie

I've had FIOS for a year or so now, and have several email accounts in Outlook 2007.  These are IMAP and POP accounts hosted at 3 different webhosts; no Verizon accounts.

All but 1 have been using port 25 for the outgoing server.  (Heck; they've been using port 25 since I signed up with Verizon about 12 years ago!)

Today, suddenly, port 25 no longer works...meaning, all email accounts using port 25 stopped sending email.  Receiving fine; just no sending.  Other accounts that use other ports send just fine.

Huh??

I contacted one webhost; and they suggested I try a different outgoing port...it worked.  So they said it must be that my ISP has started blocking port 25.

i called Verizon support and was placed on ignore...err, I mean "hold"...for an hour, and never got to actually speak to a human; so I couldn't confirm with them.  Thought I'd sign up here and see if anybody else had this issue today.

Oh, and no...nothing changed in my network setup.

Oddly, grc.com shields up says my port 25 is open!  ???

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Re: Did Verizon just shut down port 25?
prisaz
Legend

Verizon has been blocking port 25 for outgoing for some time. Spam prevention. Port 25 is not blocked to Verizon smtp hosts. outgoing.verizon.net etc. If you are using and alternate port then that works. That is what most people have been doing, so why bother port 25 is my question? Port 25 is blocked for residential accounts that run a dynamic IP, but if you have a business account then no ports are blocked. Unfortunately outgoing port 25 and incoming port 25 are used for running a mail server, and servers are restricted on residential account. I myself do not think any ports should be blocked, including incoming port 80, after all we are paying for internet service, and net neutrality laws should come into play here. Errr from me too.

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Re: Did Verizon just shut down port 25?
StuffOfInterest
Enthusiast - Level 3

Port 25 is blocked by many (if not most) Internet service providers.  This is done to stop spam-bots, as mentioned by prisaz other poster.  Most e-mail providers (such as GMail or Yahoo) provide an alternate outgoing port which can be used along with authentication to send e-mail.

One discovery I made over the weekend is that Verizon's Yahoo outgoing e-mail server will not accept e-mail with a "from" address other than  one of their valid addresses.  This keeps me from sending my outgoing GMail messages via the Verizon server.  This is likely one more security feature to keep the spam-bots under control.

Most likely you can send your e-mail, you just have to do a little more research on the settings necessary for each account you work with.

I have mixed feelings regarding port-80 blocking.  One one hand, I do web development work at home and it would be handy to remotely test sites during development without having to remap the web server to anothe port.  On the other hand, I see a lot of hacking attempts coming in via port-80, which many users would not know to look out for.  On the gripping hand, I'm sure Verizon is mainly concerned about someone (or some hacker)  trying to setup a massive file sharing site using their home service account rather than a business account.

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Re: Did Verizon just shut down port 25?
somegirl
Champion - Level 3

You should go check out Verizon's FAQ page for the port 25 change: http://www.verizon.net/port25

You might also find this thread helpful: Port 25 HSI Emailing Issues

Long story short, Verizon is blocking SMTP access on port 25 for 3rd-party domains. This is the industry standard, not something only Verizon is doing. They are actually a bit behind the times with this change, and finally catching up.

You can:

Use an alternate port (if available) for your 3rd-party outgoing server.

Use Verizon's outgoing server, or a 3rd-party server that allows an alternate port. (Such as Gmail.)

Use the web-based email service (if available) for your 3rd-party provider.

Hopefully this clears up some of the confusion.