[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Is your ISP blocking outgoing port 25?
- Subject: Is your ISP blocking outgoing port 25?
- From: johnl at iecc.com (John Levine)
- Date: 18 Jun 2009 20:18:49 -0000
- In-reply-to: <01aa01c9f04c$1d0a8820$e76ed48d@zhiyunpc>
>I wonder which ISPs are still doing so. I know comcast has been doing
>that but they cancelled it after many complaints. It seems to be the
>same case for Verizon.
You're mistaken. Comcast most certainly does port 25 filtering,
although not necessarily on every line at every moment. So does
Verizon, AT&T, and every other large North American consumer ISP I
know.
Look, kids, it's not 1998 any more. These days outgoing traffic to
port 25 is approximately 99.9% botnet spam, 0.1% GWL, and 0%
legitimate mail. Blame the botnet herders and the vendors of cruddy
software that year after year still is full of trivial exploits. If
you can make the botnets go away, I will be happy to lead the charge
to unblock all those ports.
If it's important to you to have an unfiltered connection, pay for
business service that has a static IP, or arrange to tunnel to some
host that does.
R's,
John