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Warning - Reverse DNS does not match SMTP Banner

Discussion in 'E-mail Discussions' started by chris12892, Apr 21, 2010.

  1. chris12892

    chris12892 Registered

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    Hi,

    When I run Network Tools: DNS,IP,Email on my server, I get
    "Warning - Reverse DNS does not match SMTP Banner"

    Anybody know what this means or how to fix it?

    Thanks!
     
  2. Eric

    Eric Administrator
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    Howdy,

    You have two options:

    1 Change the PTR pointer to the name of the server.

    2 Rename the server to what the PTR is.

    I say option one, but that's just me :D
     
  3. sehh

    sehh Well-Known Member

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    You need to modify your /etc/exim.conf, search for "smtp_banner". You'll have to apply the change every time cPanel makes a new exim configuration.

    I've made SO many changes to my exim.conf that I've created a simple patch that I apply via a cron job on some servers, while on other services I've just disabled auto updates (completely removed the /scripts/upcp script) and solved it permanently. When I deem necessary I enable the script and run it manually (then apply my patch as usual).
     
  4. cPanelDon

    cPanelDon cPanel Quality Assurance Analyst
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    It is not required to manually edit the Exim configuration for a simple change as ensuring the SMTP banner matches. The hostname is automatically used for the SMTP banner; if the hostname does not match the reverse DNS (PTR) record then it should be corrected by the server administrator, that is, correcting either the server hostname or the reverse DNS (PTR) record.

    Please refer to the options described by cPanelEricE as I believe you will find the change is very straight-forward and simple to accomplish: cPanel Forums - View Single Post - Warning - Reverse DNS does not match SMTP Banner

    If there is difficulty configuring the reverse DNS (PTR) record for your server IP addresses, I recommend asking the data center or server hosting provider for assistance as they will be able to point you in the right direction or may even complete the task for you. A "reverse DNS" or PTR record is a unique record for each IP address that refers it back to a domain name, such as a server hostname. Each IP address should have an accompanying PTR record for "reverse DNS." Depending on who controls the IP addresses that the server uses, it may be necessary to ask the upstream data center for assistance or to make the change on your behalf as it can only be performed by the authoritative-entity that controls reverse DNS for the IP addresses being utilized, unless they have delegated authority allowing you to edit and or host your own PTR records for reverse DNS.

    To view your current PTR records, use the following command via SSH access, replacing $IP with the desired server IP address:
    Code:
    # dig -x $IP
    To view who has authority to edit reverse DNS for a specific IP, use the following command, replacing $IP as needed:
    Code:
    # whois $IP
     
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