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myhostname and PTR

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  • Titanus Eramius
    Hello I ve searched several times about information on the PTR record, and what myhostname in main.cf should be. The problem is not the information, but the
    Message 1 of 5 , Jun 21, 2013
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      Hello

      I've searched several times about information on the PTR record, and
      what myhostname in main.cf should be. The problem is not the
      information, but the fact that I struggle to understand it...

      This server runs with the IP address 46.21.105.38 from a hosted VPS, and
      using dig to do a reverse lookup gives
      46-21-105-38-static.serverhotell.net.

      Does this means I should use 46-21-105-38-static as myhostname?

      Thanks, titanus
    • Newton Pasqualini Filho
      Sure! Or you can request to change this on your provider. Best regards Newton Pasqualini Filho newtonpasqualini@gmail.com
      Message 2 of 5 , Jun 21, 2013
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        Sure!

        Or you can request to change this on your provider.

        Best regards
        Newton Pasqualini Filho
        newtonpasqualini@...



        Em 21/06/2013, às 12:24, Titanus Eramius <titanus@...> escreveu:

        > Hello
        >
        > I've searched several times about information on the PTR record, and
        > what myhostname in main.cf should be. The problem is not the
        > information, but the fact that I struggle to understand it...
        >
        > This server runs with the IP address 46.21.105.38 from a hosted VPS, and
        > using dig to do a reverse lookup gives
        > 46-21-105-38-static.serverhotell.net.
        >
        > Does this means I should use 46-21-105-38-static as myhostname?
        >
        > Thanks, titanus
      • DTNX Postmaster
        ... Request a change from your provider, if it is not possible to change this through whatever control panel they provide. Choose a name in a domain that you
        Message 3 of 5 , Jun 21, 2013
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          On Jun 21, 2013, at 17:26, Newton Pasqualini Filho <newtonpasqualini@...> wrote:

          > Sure!
          >
          > Or you can request to change this on your provider.

          Request a change from your provider, if it is not possible to change
          this through whatever control panel they provide. Choose a name in a
          domain that you control, in the form of 'hostname.domain.tld'. Use this
          as the hostname, mailname, in your MX records, and so on.

          The reason for this is that records that contain the IP address may get
          you filtered.

          If you do not have a domain you control, register one. Avoid .info, .pw
          as top-level domains for this.

          Make sure you create the A record for '46.21.105.38' first. Many
          automated PTR control panel tools will check whether it exists.

          Mvg,
          Jona

          --

          > Em 21/06/2013, às 12:24, Titanus Eramius <titanus@...> escreveu:
          >
          >> Hello
          >>
          >> I've searched several times about information on the PTR record, and
          >> what myhostname in main.cf should be. The problem is not the
          >> information, but the fact that I struggle to understand it...
          >>
          >> This server runs with the IP address 46.21.105.38 from a hosted VPS, and
          >> using dig to do a reverse lookup gives
          >> 46-21-105-38-static.serverhotell.net.
          >>
          >> Does this means I should use 46-21-105-38-static as myhostname?
          >>
          >> Thanks, titanus
          >
        • Noel Jones
          ... Ideally, the PTR, A record, and HELO hostname should all agree. ... There doesn t appear to be a matching A record for that PTR, so the setup is
          Message 4 of 5 , Jun 21, 2013
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            On 6/21/2013 10:24 AM, Titanus Eramius wrote:
            > Hello
            >
            > I've searched several times about information on the PTR record, and
            > what myhostname in main.cf should be. The problem is not the
            > information, but the fact that I struggle to understand it...

            Ideally, the PTR, A record, and HELO hostname should all agree.

            >
            > This server runs with the IP address 46.21.105.38 from a hosted VPS, and
            > using dig to do a reverse lookup gives
            > 46-21-105-38-static.serverhotell.net.

            There doesn't appear to be a matching A record for that PTR, so the
            setup is incomplete. Postfix will label such a host as "unknown".
            Most sites (but not all!) will still accept your mail.

            Best to request your hosting company to give you a custom PTR with
            your domain name, something like smtp.example.com, mx1.example.com,
            mail.example.com, etc. so your server looks like a mail server and
            not a random infected bot. If this host handles several domains,
            just pick one for the PTR and A record. No need to list them all.

            Whatever PTR you end up with, there should be a matching A record
            with the server address.

            >
            > Does this means I should use 46-21-105-38-static as myhostname?

            While technically correct to use the
            46-21-105-38-static.serverhotell.net hostname, that's the same name
            a random infected bot will use and should be avoided.

            I would still suggest a myhostname setting that makes you look like
            a mail server instead of a random bot, even if it doesn't match the
            PTR. Make sure you also have an A record set for the hostname that
            points back to your server's IP.




            -- Noel Jones
          • Titanus Eramius
            Thank you for the replys, they are very helpful. I own this domain, and the danish handler of .dk allows all settings in DNS to be altered, but the hosting
            Message 5 of 5 , Jun 22, 2013
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              Thank you for the replys, they are very helpful.

              I "own" this domain, and the danish handler of .dk allows all settings
              in DNS to be altered, but the hosting provider does not. All records
              besides PTR is within my control at the provider, so I guess it's a
              design decision they have taken, and I will contact them about this.


              Cheers
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