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Can't recieve or send mails outbounded mails

    Question

  • Dear Exchange-experts,

    I can't send to other domains than mine domain, and I also don't recieve e-mails from other domains. My DNS records are correct. My ISP blocks port 25 by default so I obtained to use now port 2525 for smtp. 

    What can I do?

    Kind regards,
    Ruben

    Monday, January 9, 2017 9:36 PM

All replies

  • default port is 25 for SMTP as all other domain who send to you will telnet on 25 Port

    work with ISP and ask to unblock the port


    sachin hodge

    Monday, January 9, 2017 11:43 PM
  • That's like saying that you want your cell phone to send and receive using a different frequency.  You might be able to achieve that, but nobody else will talk to it.

    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."
    Celebrating 20 years of providing Exchange peer support!

    Tuesday, January 10, 2017 3:15 AM
    Moderator
  • Hi,

    Generally no ISP blocks internet port 25, this must be open for mail communication. If your ISP blocked the port particular to the IP assigned to your company, it may because there are spam generated from your end in past. You may discuss with your ISP to open the port, and ensure them for no spamming (open relay), and/or ask them to use a smarthost to send mails to avoid spamming. If still your ISP deny to open the port then change the ISP.


    • Edited by PK Sarangi Tuesday, January 10, 2017 7:45 AM
    Tuesday, January 10, 2017 7:44 AM
  • Oh, PK Sarangi, you're very wrong there.  Many ISPs block TCP port 25 in their residential-class services, which is one way they differentiate them from their business-class services and require customers to relay mail through the ISP's SMTP server.  Part of the reason for that is to stop spam from the usually poorly protected residential PCs.  The real answer to the question is to buy an appropriate class of service from your ISP.

    Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."
    Celebrating 20 years of providing Exchange peer support!

    Wednesday, January 11, 2017 7:57 AM
    Moderator
  • Hi Ed Crowley, I agreed on your point. 

    Wednesday, January 11, 2017 3:49 PM