Nslookup by IP and name don't have matching IP

[Udgnim]

made up example of what I'm seeing

perform nslookup for 1.1.1.1 which returns mail.asdf.com

perform nslookup for mail.asdf.com which returns 2.2.2.2

the MX & A record for mail.asdf.com points to 2.2.2.2 which is an email security appliance device.

1.1.1.1 is the public address the mail server is using to send email with. no PTR record is set up.

Can anyone provide some information or have an idea on what is happening? I don't understand how performing a nslookup of 1.1.1.1 returns mail.asdf.com when I don't see a DNS record that matches with that.

I'm guessing I'm lacking some knowledge on how nslookup works when translating an IP address to a FQDN.

 

[Red Squirrel]

The PTR record is probably provided by the provider of the IP. It's typical when you are leasing a server/IP space. The provider most likely has an option for you to change what it resolves to.

 

[Nothinman]

made up example of what I'm seeing

perform nslookup for 1.1.1.1 which returns mail.asdf.com

perform nslookup for mail.asdf.com which returns 2.2.2.2

the MX & A record for mail.asdf.com points to 2.2.2.2 which is an email security appliance device.

1.1.1.1 is the public address the mail server is using to send email with. no PTR record is set up.

Can anyone provide some information or have an idea on what is happening? I don't understand how performing a nslookup of 1.1.1.1 returns mail.asdf.com when I don't see a DNS record that matches with that.

I'm guessing I'm lacking some knowledge on how nslookup works when translating an IP address to a FQDN.

Forward and reverse zones are maintained separately, you need to contact whoever owns the IP to have the PTR record for it changed.