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Get bounce back RDNS

    Question

  • Hi, 
    We are receiving this bounce back from this one particular external domain. 

    smtp;550 No RDNS entry for 175.a.x.141

    our mx : mail.x.shm.com = 175.a.x.140

    our ptr : 175.a.x.140 = mail.x.shm.com 

    175.a.x.141 is our WAN 1 interface of the firewall.

    Why does the external domain reject the RDNS.


    knizam

    Friday, February 19, 2016 2:13 AM

Answers

  • RDNS has to be in place for the IP address you're sending from, not necessarily the IP address for the servers pointed to by your MX record.

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

    Friday, February 19, 2016 9:08 AM
    Moderator

All replies

  • RDNS has to be in place for the IP address you're sending from, not necessarily the IP address for the servers pointed to by your MX record.

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

    Friday, February 19, 2016 9:08 AM
    Moderator
  • Yes. i figure it out.

    It is all NAT of the Exch Server. Exch Server need to be OUTBOUND using .140.

    Thanks.


    knizam

    Friday, February 19, 2016 11:18 PM
  • You're welcome.  Happy to have helped.

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

    Saturday, February 20, 2016 12:02 AM
    Moderator