know if port 25 is open

Discussion in 'HOWTO-Related Questions' started by jenks, Nov 27, 2009.

  1. jenks

    jenks New Member

    Hello forum,

    I've been looking around for info on this, but can't seem to find it!

    I'm on a 3mobile "dongle" internet connection. I try to send an email via telnet,but all i see is "could not open connection to host,on port 25"

    I would like to know how can i tell if port 25 is open?



    I hope im in the rite forum!
    Last edited: Nov 27, 2009
  2. falko

    falko Super Moderator ISPConfig Developer

    Please ask your provider if they block port 25.
  3. jenks

    jenks New Member

    It seems they do block port 25.Does this mean i cannot email throught telnet?
  4. Miguel

    Miguel New Member HowtoForge Supporter

    I had the same problem. A lot of ISP's block port 25 in general and open port 25 only to given IP's, like for example their own smtp servers. This to avoid spamming via pc's that have a smtp server running or mis configured smtp servers that act as open relays.

    If you own the mailserver, either add a PAT rule to redirect port 26 (or another FREE port) to port 25 or have your smtp server listen on port 25 and add another port.

    That way you can connect to your smtp server on another port than 25 that is not blocked by the ISP.

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