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SMTP Banner matches Reverse DNS except on SMTP SSL

Discussion in 'E-mail Discussions' started by Miguel Brito, Jul 22, 2016.

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  1. Miguel Brito

    Miguel Brito Registered

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    Hello. Please excuse my english, it's not my main lang.

    I'm having trouble setting my vps server to keep mail from being sent to spam filters in hotmail, gmail, yahoo, and many more.
    This server shares one ip for all services/accounts

    SSL certificates, DKIM, spf, DMARC and RDNS are properly set up, but when i run the unlocktheinbox.com paid test, this are the results :



    As you can see there is only one critical error:

    Code:
    SMTP SSL (Port 465):    Connection Established
    - Time To Connect:    1 Seconds - Passed
    - Extensions:    SIZE, 8BITMIME, PIPELINING, AUTH, HELP
    - Server Greeting:    jupiter.example.com ESMTP Exim 4.87 #1 Fri, 22 Jul 2016 10:57:48 +0000
    We do not authorize the use of this system to transport unsolicited,
    and/or bulk e-mail.
    - SSL Hostname:    jupiter.example.com
    - SSL Subject:    CN=jupiter.example.com, OU=PositiveSSL Multi-Domain, OU=Domain Control Validated
    - SSL Issuer:    CN=COMODO RSA Domain Validation Secure Server CA, O=COMODO CA Limited, L=Salford, S=Greater Manchester, C=GB
    - SMTP Banner Reverse DNS Check:    Failed - SMTP Banner/Greeting Does not contain your hostname
    - SSL Valid:    Certificate is Valid
    - SSL Key Size:    2048
    - SSL Protocol Used:    TLS 1.2
    - SSL Cipher Algorithm:    AES 256
    - SSL Hash Algorithm:    SHA 384
    - SSL Exchange Algorithm:    ECDH
    - SSLv3 Disabled:    Yes
    Normal SMTP on port 25 does not have this rDNS problem. As i said, rDNS is propperly set to match the server IP.

    ¿Can you give me some advice?
     
    #1 Miguel Brito, Jul 22, 2016
    Last edited by a moderator: Jul 22, 2016
  2. Miguel Brito

    Miguel Brito Registered

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    continuation:

    - SMTP Banner Reverse DNS Check: Failed - SMTP Banner/Greeting Does not contain your hostname


    only that there is:

    - Server Greeting: jupiter.example.com ESMTP Exim 4.87 #1 Fri, 22 Jul 2016 10:57:48 +0000
    We do not authorize the use of this system to transport unsolicited,
    and/or bulk e-mail.


    I wanted to share the mail test results link, but moderator took it out as i'm probably violating rules in this forum, for which i apologize. But i will try to share it here: - Removed, no need here -
     
    #2 Miguel Brito, Jul 22, 2016
    Last edited by a moderator: Jul 22, 2016
  3. twhiting9275

    twhiting9275 Well-Known Member

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    If this is the only test failing, I'd say ignore it. Most people should be using hostname , port 25 anyways.
    As long as hostname, port 25 matches your hostname, then you're all good.
     
  4. Miguel Brito

    Miguel Brito Registered

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    thanks for your kind and fast answer, but it's not only the test, i forgot to mention that all mail sent from server is going to spam on hotmail, gmail, yahoo, and more.
     
  5. twhiting9275

    twhiting9275 Well-Known Member

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    It's doubtful that this is caused by your SMTP banner, honestly. Like I said, as long as your smtp banner matches your server name, you should be good.

    A couple of things to check here

    1: Make sure you're not blacklisted anywhere. I use MX Toolbox and Multi-RBL (both free services) to check. Plug your server IP in there.

    2: If you're using php scripts to send mail, make sure you implement smtp, not utilizing php's default mail() functionality. The latter tends to throw red flags with mail providers, while the former doesn't so much.
     
  6. Miguel Brito

    Miguel Brito Registered

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    i'm using roundcube to send mail, and current ip is not in any blacklist, i don't know what's going on
     
  7. cPanelMichael

    cPanelMichael Forums Analyst
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