Add a non resolving domain in white list

Discussion in 'Installation/Configuration' started by, Jan 9, 2020.

  1. Member


    In our email server, I want to add following domain

    Error we get in maillog is following
    <EOSEXCH.CPIPL.CO.IN>: Helo command rejected: Host not found;

    I want to add EOSEXCH.CPIPL.CO.IN domain as a white list domain

    Shall I add one entry in etc/resolve or /etc/hosts?
  2. Taleman

    Taleman Well-Known Member HowtoForge Supporter

    That domain does not exist in name service.
    Host EOSEXCH.CPIPL.CO.IN not found: 3(NXDOMAIN)
    I do not see how it could work as e-mail domain, except internally in your LAN if you set it up in internal name service.
    If there is a name server that can resolve that domain, add that name server to /etc/resolv.conf. If that is not a domain but a FQDN hostname, add that hostname to /etc/hosts. Then the host with that line in /etc/hosts can resolve that hostname to IP number.
  3. Steini86

    Steini86 Active Member

    Depends on your postfix configuration. I can only guess, but you have some kind of helo restriction in place.
    To whitelist, you could do:

    smtpd_helo_restrictions =
      check_helo_access hash:/etc/postfix/check_helo_access
    /etc/postfix/check_helo_access sender_white_list
    I doubt that it works right out of the box, because this depends on your other configuration. The postfix manual will help you.

    after reading your post again, it could be that this is not what you actually want. You said something about "adding a new domain". Can you explain better what you want to achieve?
  4. Member

    The exact error line is like this

    Jan 5 03:59:02 linode postfix/smtpd[12785]: connect from[]
    Jan 5 03:59:04 linode postfix/smtpd[12785]: NOQUEUE: reject: RCPT from[]: 450 4.7.1 <EOSEXCH.CPIPL.CO.IN>: Helo command rejected: Host not found; from=<[email protected]> to=<[email protected]> proto=ESMTP helo=<EOSEXCH.CPIPL.CO.IN>

    Since the EOSEXCH.CPIPL.CO.IN is not resolving, my postfix is not accepting the emails from them.

    Their IT administrator says it is resolving from everywhere except your email server. They have setup local DNS server

    They are not able to fix it after lot of explanations and I dont want to loose my client because he is not able to receive emails from eospower.

    So I am adding a fixed domain-ip combination in my system, so that postfix can receive emails.
  5. Steini86

    Steini86 Active Member

    They are wrong, its not resolving. But you can't do anything about that.
    Sounds good. I have shown you how to do that.
    Alternatively you can weaken your helo restrictions to allow invalid hosts:

    Negative side effect could be more spam
  6. Member

    I have also added record in helo_access

    /^182\.76\.82\.211$/ PERMIT
    Jesse Norell likes this.

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