[SOLVED] 450 4.7.25 Client host rejected: cannot find your hostname,

Discussion in 'Mail Gateway: Installation and configuration' started by killmasta93, Sep 26, 2018.

  1. killmasta93

    killmasta93 Member

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    Hi,
    I was wondering if someone could shed some light on the issue im having. Currnelty have disabled smtp helo checks, and greylist disabled and SPF disabled also. but i keep getting the

    Code:
    450 4.7.25 Client host rejected: cannot find your hostname,

    any ideas?

    Thank you
     
  2. IEM

    IEM Member

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    i find that sometimes postfix does not get restarted when changing things in the web-interface (the last thing i remember that failed to restart was when enabling/disabling SPF).

    i usually resort to changing the smtp-banner as well, which
    - seems to restart postfix
    - allows me to do a simple check whether postfix was indeed restarted (if it shows the new banner, the restart was succesfull)
     
  3. tom

    tom Proxmox Staff Member
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    Seems your public DNS entries are not set correctly?
     
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  4. IEM

    IEM Member

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    i think the question is more targeted towards: "which checks must be disabled to accept connections from IPs with incorrect public DNS entries?"
     
  5. tom

    tom Proxmox Staff Member
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    Please check your settings on "Configuration/Mail Proxy/Options: Reject Unknown Clients / Senders"
     
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    killmasta93 likes this.
  6. killmasta93

    killmasta93 Member

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    Thank you tom, that did the trick, i the difference from clients and senders would be?
     
  7. heutger

    heutger Active Member

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    Unknown clients are hostnames not matching or existing (FCrDNS) of the sending mailserver, unknown senders checks, if the domain of the sender address exists.
     
    killmasta93 likes this.
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