Monday, May 3

Verizon to block outbound port 25 for residential customers

For those of you that have Verizon Home Internet (FiOS or other), Verizon is about to start blocking outbound port 25.


Why is Verizon blocking outbound port 25?

The majority of spam (unsolicited email) on the Internet is caused by malicious software viruses that take control of infected computers. These viruses direct the infected machines to send email through port 25. Verizon takes spam very seriously. Verizon blocks outgoing connections on port 25 to prevent infected computers from being used by spammers to send unsolicited email. Outbound port 25 blocking is a standard industry method to control spam.

For more information, click the link below:

Verizon | High Speed Internet - Your Attention Needed: Re-configure Your Email Settings to Send Email.


Tweets that mention Verizon to block outbound port 25 for residential customers -- said...

[...] This post was mentioned on Twitter by Mike Fratto and JoelEsler, Jason Kendall. Jason Kendall said: RT @JoelEsler: Verizon to block outbound port 25 for residential customers [...]

foxyproxyuser said...

Turk Telekom does the same in Turkey. Our subsidiaries cannot sent mails...

pj said...

About freaking time! The volumes of spam from Verizon residential service machines has been horrendous for YEARS

Joel Esler said...


anthonygartner said...

That was a fix that was put in by most ISP's years ago... Verizon is just getting to it really????

Bill Bradford said...

That link says "We will begin implementing outbound port 25 blocking in the first quarter of 2009."

Joel Esler said...

Yes, but this was a recent post from a friend at Verizon. I wonder if that
is a typo.

Joel Esler said...

Also good. Another interesting thing that I just remembered is, most mail
clients set up these connections on secure ports by default.
actually figures out which port it should use by testing them. I think
Thunderbird does as well.