Fix reverse DNS problem
I have two Linodes; domain names are malibyte.com and malibyte.net.
Problem #1: Reverse DNS on the malibyte.net server is not showing up via the "host" command (on either one of the nodes or on an "outside" machine), even though it appears configured correctly on the node's networking page. The malibyte.com server's reverse DNS with the Linode-assigned IPv4 address comes up correctly in all cases.
rcs@obi-wan:~$ host 45.56.92.87
87.92.56.45.in-addr.arpa domain name pointer mulder.malibyte.com.
This is correct.
However, on malibyte.net, there's no entry there. In my zone files and the in-addr-arpa files, everything appears set up OK.
rcs@obi-wan:~$ host 66.175.218.201
201.218.175.66.in-addr.arpa has no PTR record
Problem #2: This is not Linode's issue but I need help with it. Both of these servers previously had static IP addresses through Time Warner Business (now Spectrum). If I do a reverse-DNS lookup on the old IP addresses, my server hostnames still come up. I have called Spectrum, and they told me that these IP address are no longer linked to my servers in their systems. There is no mention of those old IP addresses anywhere on my servers (grep -r). Obviously, if my server hostnames are still linked to old IPs, there will be problems. Any advice on tracking this down and how to fix it? The PTR records in the in-addr-arpa zone files on my nodes are currently correct.
Any help appreciated! Thanks.
3 Replies
rdaniels
Linode Staff
Hey @Malibyte!
I'm sorry to hear that you're having an issue with rDNS. I'd be happy to help answer your questions.
Problem #1
Taking a look at the whois for your domain, I notice that there are two additional name servers listed.
whois malibyte.net
Name Server: kenobi.malibyte.net
Name Server: mulder.malibyte.com
Name Server: ns1.linode.com
Name Server: ns2.linode.com
Name Server: ns3.linode.com
Name Server: ns4.linode.com
Name Server: ns5.linode.com
You'll need to remove the first two sites from you registrar's page in order for the domain to resolve properly every time. It looks like the first two are what you have set for your rDNS, and they are currently resolving correctly.
host 45.56.92.87
87.92.56.45.in-addr.arpa domain name pointer mulder.malibyte.com.
host 66.175.218.201
201.218.175.66.in-addr.arpa domain name pointer kenobi.malibyte.net.
Problem #2
The issue you are seeing may have been temporary. It typically takes about 24-48 hours for DNS changes to propagate across the Internet. You should be fine as long as your registrar has the correct IP address.
I hope this was helpful!
Found the problem was a misconfiguration on my registrar's site. All fixed. Sorry for wasting your time. Thanks!