Please whitelist cPanel in your adblocker so that you’re able to see our version release promotions, thanks!

The Community Forums

Interact with an entire community of cPanel & WHM users!
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

SOLVED Reverse DNS does not match SMTP Banner

Discussion in 'E-mail Discussions' started by DennisMidjord, Dec 1, 2017.

  1. DennisMidjord

    DennisMidjord Well-Known Member

    Joined:
    Sep 27, 2016
    Messages:
    115
    Likes Received:
    7
    Trophy Points:
    18
    Location:
    Denmark
    cPanel Access Level:
    Root Administrator
    Hi,

    MXToolBox reports that our reverse DNS does not match the SMTP Banner even though it should.
    I've made the following changes:
    Exim configuration:
    Send mail from account’s dedicated IP address: Off
    Reference /etc/mailhelo for outgoing SMTP HELO: On
    Reference /etc/mailips for outgoing SMTP connections: On

    Code:
    smtp_banner = "${smtp_active_hostname} ESMTP Exim ${version_number}  \#${compile_number} ${tod_full} \n   We do not authorize the use of this system to transport unsolicited, \n   and/or bulk e-mail."
    
    smtp_active_hostname =
    ${lookup{$interface_address}lsearch{/etc/mail_reverse_dns}{$value}{$primary_hostname}}
    
    message_id_header_domain = $smtp_active_hostname
    /etc/mailips:
    Code:
    *: 10.0.0.251
    /etc/mail_reverse_dns:
    Code:
    10.0.0.251: pro5mail.example.com
    /etc/mailhelo:
    Code:
    * : pro5mail.example.com
    When trying to telnet, it reports the correct hostname:
    Code:
    [root@server10 ~]# telnet pro5mail.example.com 25
    Trying *.*.*.251...
    Connected to pro5mail.example.com.
    Escape character is '^]'.
    What could the issue be?
     
  2. cPanelMichael

    cPanelMichael Forums Analyst
    Staff Member

    Joined:
    Apr 11, 2011
    Messages:
    41,516
    Likes Received:
    1,616
    Trophy Points:
    363
    cPanel Access Level:
    Root Administrator
    Hello,

    Sometimes it's a false positive from the MXToolBox website due to the "Introduce a delay into the SMTP transaction for unknown hosts and messages detected as spam." option under the "ACL Options" tab in "WHM >> Exim Configuration Manager >> Basic Editor". See:

    SOLVED - Reverse DNS does not match SMTP Banner (Problem)

    Thank you.
     
  3. DennisMidjord

    DennisMidjord Well-Known Member

    Joined:
    Sep 27, 2016
    Messages:
    115
    Likes Received:
    7
    Trophy Points:
    18
    Location:
    Denmark
    cPanel Access Level:
    Root Administrator
    Disabling that option temporarily also shows only green checkmarks on MXToolBox. Thanks, Michael!
     
    cPanelMichael likes this.
Loading...

Share This Page