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Sebastian Ries wrote:
> Hi there
>
> I just want to know some opinions on the following DNS Setup for a mail
> server:
>
> # host -t MX example.com
> example.com mail is handled by 100 mail.example.com.
>
> # host mail.example.com
> mail.example.com is an alias for hostname.example.com.
> hostname.example.com has address 1.2.3.4
>
> # host 1.2.3.4
> 4.3.2.1.in-addr.arpa domain name pointer hostname.example.com.
>
> The mailserver (postfix) connects saying it is hostname.example.com.
>
>
> Should this be a correct setup?


It looks like CNAME error. See RFC 974 ;;

> One partner we want to send mails to does BOUNCE mails with
> 554 5.7.1 DNS Blacklisted by in-addr.arpa (in reply to MAIL FROM
> command)
> Do you think this is correct?
>
> I think this also prevents from getting mail from googlemail:
> sr@ben:~$ host -t MX googlemail.com
> googlemail.com mail is handled by 5 gmail-smtp-in.l.google.com.
> googlemail.com mail is handled by 10 alt1.gmail-smtp-in.l.google.com.
> googlemail.com mail is handled by 10 alt2.gmail-smtp-in.l.google.com.
> googlemail.com mail is handled by 50 gsmtp147.google.com.
> googlemail.com mail is handled by 50 gsmtp183.google.com.
> sr@ben:~$ host gmail-smtp-in.l.google.com.
> gmail-smtp-in.l.google.com has address 209.85.129.27
> gmail-smtp-in.l.google.com has address 209.85.129.114
> sr@ben:~$ host 209.85.129.27
> 27.129.85.209.in-addr.arpa domain name pointer fk-in-f27.google.com.
>
> Is this true?


Google is true. That's basic rule of DNS ;;

> Regards
> Sebastian Ries
>


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