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exim can detect the presence of the A record && absence of the PTR record with ACL and then any action can be performed via routers. $sender_host_name, $host_lookup_failed and $host_lookup_deferred do all the trick. The problem is that spammers are often use such poorly configured but still legal hosts for submission (ISP's dynamically addressed ...


There are few services that require a PTR record. Most services neither require nor make use of PTR records. In some cases, administrators may use PTR records to perform some validation before granting access to services. In this case, they should be aware of whether or not PTR records are available. If they are aware the PTR records should not exist for ...


Modify those in /etc/ssh/sshd_config Port 22, UseDNS yes, UsePAM no, UseLogin no, And make: service sshd restart


The problem seems to be that you have other servers than your mail server listed in your MX record, one of which has a lower priority. MX records work on a lowest-priority-first basis, which means the internet is first of all trying to send mail for your domain to, which doesn't seem to know anything about your domain. At this point, ...


Both and resolve to the same address, which is a bad idea in itself if these are supposed to be your "nameservers". As for (delegated to the above "nameservers"), responds with status REFUSED, presumably because you have no such zone configured. (If the config included in the ...


Now my question is, is it possible to point that IP to my domain name? Yes, RDNS - reverse lookup. It is not really relevant though, because... they need a static IP. If they need a static IP, then they need a static IP. Likely their system is simlly programmed not to use any DNS lookup at all, and playing around with more unusual DNS setups is just ...


No, this is not possible at all (to be clear: Not possible for your use case. See TomTom's answer where he talks about RDNS. This is not what you want). Depending on the protocol, you could set up a load balancer on one static IP address and then forward the requests to multiple other servers.


Google won't configure reverse DNS for you If you had a carrier such as AT&T or an EC2 instance, they offer reverse DNS services. As of know, Google does not offer this. It is rumored they will remediate this at some point but as of now the service is unavailable.


Ask google to do it, reverse dns can be changed only by owner of IP sunbet thru reverse zone. But I personally don't believe it can be done.

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