about the A and PTR for sending mail

[Hauke Lampe]

On 10.11.2011 02:57, 风河 wrote:

> I have two server IPs, the A records for them are:
> 
> mail.dnsbed.com.        300     IN      A       74.117.233.4
> mail.dnsbed.com.        300     IN      A       74.117.232.204
> 
> The corresponding PTR records are:
> 
> 4.233.117.74.in-addr.arpa. 36466 IN     PTR     dnsbed.com.
> 204.232.117.74.in-addr.arpa. 36453 IN   PTR     dnsbed.com.

The forward lookup for dnsbed.com returns:;
173.245.61.41
173.245.61.115

The reverse entries for your nameserver don't have to match your
mailserver name but they must be consistent, i.e. the reverse must
resolve forward to the IP address.

mail.dnsbed.com -> 74.117.233.4 -> dnsbed.com -> 74.117.233.4 would be a
consistent reverse/forward loop.

mail.dnsbed.com -> 74.117.233.4 -> dnsbed.com -> 173.245.61.41 is not

Maybe the easiest way would be to change the PTRs of
4.233.117.74.in-addr.arpa. and 204.232.117.74.in-addr.arpa to
"mail.dnsbed.com", so you don't have to move the A records of dnsbed.com


HTH,
Hauke.

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