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rDNS change/fix

Rich22
Newbie
Posts: 4
Registered: ‎04-07-2023

rDNS change/fix

Hi,

I've tried technical support but unfortunately they weren't able to help. I've seen several similar posts to this so hoping someone can help.

My rDNS was originally (years ago) myusername.plus.com and i had it changed to make it more anonymous so it's currently in the form xxx-xxx-xxx-xxx.plus.com but if you look that up it says record not found.

It seems to be broken as it doesn't look back up to my IP correctly.

Please can it be reset to work correctly so that if you lookup my rDNS it correctly points back to my IP address?

Thanks! Smiley

 

7 REPLIES 7
MisterW
Superuser
Superuser
Posts: 15,324
Thanks: 5,876
Fixes: 421
Registered: ‎30-07-2007

Re: rDNS change/fix

A forward lookup on the rDNS PTR will never work. https://www.cloudflare.com/en-gb/learning/dns/dns-records/dns-ptr-record/

<username>.plus.com will return your IP in a forward lookup irrespective of what the rDNS for your IP is set to

Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.

Rich22
Newbie
Posts: 4
Registered: ‎04-07-2023

Re: rDNS change/fix

If my PTR record was 88-88-88-88.plus.com though shouldn't I be able to lookup that address as an A record and it point back at my IP? so you can look it up in both directions?

If I lookup the PTR for 8.8.8.8 using dig I get dns.google. and then if i look that up as an A record I get  8.8.8.8

If I lookup mine i get the plus.com record but if I lookup that as an A i get record not found.

The reason I'm requesting this be checked to make sure it's configured correctly is I am getting this error when trying to send emails from my server to a Gmail recipient:

"Your sending IP address must have a PTR record. PTR records verify that the sending hostname is associated with the sending IP address. Every IP address must map to a hostname in the PTR record. The hostname specified in the PTR record must have a forward DNS that refers to the sending IP address."

I think it might be that second bit which is broken on mine.

 

 

MisterW
Superuser
Superuser
Posts: 15,324
Thanks: 5,876
Fixes: 421
Registered: ‎30-07-2007

Re: rDNS change/fix

You need the rDNS PTR  set to the hostname you are using to send email

Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.

Rich22
Newbie
Posts: 4
Registered: ‎04-07-2023

Re: rDNS change/fix

Thanks for your replies.

When it was set to accountname.plus.com it resolved in both directions, is that not possible once it's been changed to something else?

MisterW
Superuser
Superuser
Posts: 15,324
Thanks: 5,876
Fixes: 421
Registered: ‎30-07-2007

Re: rDNS change/fix

It doesn't resolve in both directions. When set to accountname.plus.com it just happens to be the same as the domain used for the forward resolution

Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.

Rich22
Newbie
Posts: 4
Registered: ‎04-07-2023

Re: rDNS change/fix

Ah ok, so while it probably doesn't matter by the sounds of it, can the forward resolution (A record?) be updated to match the PTR record?

MisterW
Superuser
Superuser
Posts: 15,324
Thanks: 5,876
Fixes: 421
Registered: ‎30-07-2007

Re: rDNS change/fix

No, the A record is associated with the domain I.e accountname.plus.com , that then points to an IP address

The IP address has a PTR record which ( in theory ) can be anything , but would normally be set to the A record

Superusers are not staff, but they do have a direct line of communication into the business in order to raise issues, concerns and feedback from the community.