cPanel set PTR record for reverse DNS wrong response

zmeutz

October 13, 2025 17:11

Hi,

I have set an PTR record for reverse DNS but when I test it with hosts 0.0.0.0 or nslockup 0.0.0.0 I get a wrong domain..

for nslockup 0.0.0.0
0.0.0.0.in-addr.arpa name = baddomainname.com

and for host 0.0.0.0

0.0.0.0.in-addr.arpa domain name pointer baddomainname.com

(baddomainname I see it's ISP domain name)

also

The system uses an alternate HELO of “0.0.0.0.in-addr.arpa” when sending mail from the “ns1.gooddomainname.com” domain.

The system sends “ns1.gooddomainname.com”’s outgoing email from the “0.0.0.0” IP address. The only PTR value for this IP address must be “0.0.0.0.in-addr.arpa”. This is the name that this server sends with SMTP’s “HELO” command to send “ns1.gooddomainname.com”’s outgoing email.

1 unexpected PTR value exists for this IP address:

baddomainname.com

To fix this problem, replace all PTR records for “0.0.0.0.in-addr.arpa” with the following record at “ns1.baddomainname.com” and “ns2.baddomainname.com”:

Suggested “PTR” (PTR) Record PTR

is there any way to change domain name pointer?

Thanks!

Stefan

Comments

13 comments

cPRex Jurassic Moderator

October 14, 2025 02:02
Hey there! Your server almost certainly is not the authority for the reverse DNS for the IP address. You'll likely need to contact your hosting provider to have them configure the PTR record on their end for you, and then things will be working well.

Can you contact them to see if they can take care of that for you?
0
zmeutz

October 16, 2025 10:00
It's a personal server with a few email addresses ...

I tryed to change PTR adress, the old one with in-addr.arpa,

I have record PTR with in-addr.arpa, I cleared cache and when I test to see what address respond from nslockup or host I get the old address
0
cPRex Jurassic Moderator

October 16, 2025 13:03
It may be a personal server, but that still doesn't mean you control the PTR records. Those are usually handled by the hosting provider unless they have specifically delegated the authority to your server.
0
zmeutz

October 16, 2025 16:07
It’s a personal server that I have full control of it, I also can control PTR .

I have full control of the server
0
cPRex Jurassic Moderator

October 16, 2025 16:08
When you say it's a "personal" server, do you mean you're hosting it on a home network?
0
rbairwell

October 16, 2025 20:09

Edited
It's worth checking the delegation of PTR first as I suspect cPRex is correct (they usually are) and the PTR delegation isn't actually pointing at your server (I haven't, in over 25 years of server admin, had it delegated down to the server level) - but is actually pointing at your hosting providers/ISP.

Here's how you can check from a Linux command line (assuming your IP address is 192.168.1.2):

First randomly pick an in-addr server (these provide the "base" of all PTR/reverse allocations):
```
dig in-addr.arpa NS +short|head -1
```
I got: c.in-addr-servers.arpa . Then query that server directly for your IP address to see what it knows about it (note: as the "-x" operator is being used, there is no need to "reverse the IP address")
```
dig @c.in-addr-servers.arpa -x 192.168.1.2 NS +noall +auth
```
You'll get a list of name servers the first part is delegated to such as:

192.in-addr.arpa. 86400 IN NS y.arin.net.
192.in-addr.arpa. 86400 IN NS z.arin.net.
192.in-addr.arpa. 86400 IN NS arin.authdns.ripe.net.

Pick one and repeat such as:
```
dig @z.arin.net -x 192.168.1.2 NS +noall +auth
```
Again, you'll get a list of nameservers back such as:

1.168.192.in-addr.arpa. 86400 IN NS ns3.example.com.
1.168.192.in-addr.arpa. 86400 IN NS ns1.example.com.

and repeat. At one point, you'll stop getting a list of nameservers back and just get a list of entries such as:
```
dig @ns3.example.com -x 192.168.1.2 NS +noall +auth
```
1.168.192.in-addr.arpa. 300 IN SOA ns1.example.com. hostmaster.example.com. 1759061925 1800 900 1209600 300

If that last nameserver IS your server, then the reverse delegation (PTR) HAS been made. If it isn't, then you'll need to contact whoever maintains those nameservers (in this case whoever provides ns3.example.com who would be my datacentre provider in this case) and ask them to set the PTR record for you.
1
zmeutz

October 17, 2025 05:46
Hi!

First thanks for your detailed response!

I did as you post, but from the begining I think that I didn't set up correctly PTR...
```
dig in-addr.arpa NS +short|head -1
```
a.in-addr-servers.arpa.
```
dig @a.in-addr-servers.arpa -x 192.168.1.22 NS +noall +auth
```
192.in-addr.arpa. 86400 IN NS x.arin.net.
192.in-addr.arpa. 86400 IN NS y.arin.net.
192.in-addr.arpa. 86400 IN NS r.arin.net.
192.in-addr.arpa. 86400 IN NS arin.authdns.ripe.net.
192.in-addr.arpa. 86400 IN NS z.arin.net.
192.in-addr.arpa. 86400 IN NS u.arin.net.
```
dig @z.arin.net -x 192.168.1.22 NS +noall +auth
```
168.192.in-addr.arpa. 86400 IN NS blackhole-1.iana.org.
168.192.in-addr.arpa. 86400 IN NS blackhole-2.iana.org.
```
dig @x.arin.net -x 192.168.1.22 NS +noall +auth
```
168.192.in-addr.arpa. 86400 IN NS blackhole-2.iana.org.
168.192.in-addr.arpa. 86400 IN NS blackhole-1.iana.org.
```
dig @y.arin.net -x 192.168.1.22 NS +noall +auth
```
168.192.in-addr.arpa. 86400 IN NS blackhole-1.iana.org.
168.192.in-addr.arpa. 86400 IN NS blackhole-2.iana.org.
```
dig @r.arin.net -x 192.168.1.22 NS +noall +auth
```
168.192.in-addr.arpa. 86400 IN NS blackhole-1.iana.org.
168.192.in-addr.arpa. 86400 IN NS blackhole-2.iana.org.
```
dig @u.arin.net -x 192.168.1.22 NS +noall +auth
```
168.192.in-addr.arpa. 86400 IN NS blackhole-1.iana.org.
168.192.in-addr.arpa. 86400 IN NS blackhole-2.iana.org.
```
dig @u.arin.net -x 192.168.1.22 NS +noall +auth
```
0
RadWebHosting

October 17, 2025 13:17
I did as you post, but from the begining I think that I didn't set up correctly PTR...

Yes, that's what's being said. You'll want to have your provider update the PTR.
1
cPRex Jurassic Moderator

October 17, 2025 13:18
He also never answered where exactly the server is hosted, which is likely also key to the question.
0
rbairwell

October 17, 2025 14:17
If your server IP is 192.168.1.22 that means it is located in the reserved "private address space" and PTR records "cannot" be set for it as the IP address is not accessible on the public internet.

Are you sure your IP address for your cPanel server is 192.168.1.22?
0
cPRex Jurassic Moderator

October 17, 2025 14:19
I'm guessing that was just an example IP, although I suppose it could be a NAT.
0
zmeutz

October 17, 2025 19:13
@RadWebHosting it’s a personal server, hosted at home, I must to make changes

@cPRex I sad from the beginning, it is a personal server, I have full access, hosted at home

@rbairwell no isn’t server it, that ip it’s local ip, public ip it is 5.2.210.Xx I didn’t post it…

@cPRex yes it is just an example

I’m trying to solve this problem because I can’t send email and many of them return errors… first time I setup an wrong PTR and now I’m trying to update it but without success…

Thanks!
Stefan
0
cPRex Jurassic Moderator

October 17, 2025 19:19
I would almost guarantee you won't be able to fix this on a home-based machine. You'll have to contact the ISP, but I doubt they will be willing to adjust a PTR for a home user.
0

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