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Email port 25 26 587


Email port 25 – This is the standard outgoing email port. 99% of the time it will be fine and set in your email program by default.

Email port 26 – This is simply a alternative to port 25 and works the same. It exists because some ISP’s do not allow outgoing email which we believe unless advertised bluntly is bad business conduct. So we have set up a second port for people to get around their misleading ISP’s.

Email port 587 – Is yet another attempt to block email from users. Like most spam blocking attempts blocking all ports for email other then port 587  really does nothing other then create confusion for regular users of the internet. But if you need port 587 then DWHS can open this by request.

  • Ken
    December 9, 2009 at 10:38 am

    There’s a nice discussion of this at

  • Jerry G
    June 3, 2010 at 10:41 pm

    I’m not very technical on this … but is this only temporarily effective? Once spam “migrates” over time to port 26 or port 587 [will it?] will this be any good? Then will they just pick a new number and start the next round?

  • Ken
    June 21, 2010 at 3:34 pm

    No. Port 587 requires that you identify yourself to the server – something spammers can’t afford to do. If you’re interested in the details, the canonical sources on all this are a paper by the Messaging Anti-Abuse Working Group, available at and a proposal by the Anti-spam Technical Alliance that you used to be able to get at but can’t any more. If anyone knows where to find it please let us know.

  • Ike
    April 6, 2012 at 12:05 am

    So ISP block email, WTF!

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