Unable to setup reverse DNS
We have reverse DNS setup for our IPv4 address, but are having difficulty creating it for our IPv6 address. We have A records setup for both addresses. When I view the list of IPs for the linode I see the IPv6 address listed with the button to Edit RDNS -- but when I try to do that, it gives me the error:
No match was found for 'MYDOMAIN'. Reverse DNS must have a matching forward entry. If your entry was added to your domain service recently, it may take some time for the changes to propagate.
The A record has been in place for a couple days, so I don't think it's a propagation display issue. What else would cause this problem?
7 Replies
You have an A record with your Linode's IPv4 address, but does the name have an AAAA record with the IPv6 address?
Also, note that the Linode DNS Manager sets up the proper kind of record (A or AAAA) for the kind of address you have. The user doesn't have to make the distinction.
stevewi:~ $ dig mydomain.com
...
;; ANSWER SECTION:
mydomain.com. 86400 IN A xxx.xxx.xxx.xxx
...
stevewi:~ $ dig -6 -t AAAA mydomain.com
...
;; ANSWER SECTION:
mydomain.com. 86400 IN A xxxx:xxxx::xxxx:xxxx:xxxx:xxxx
...
-- sw
In the Linode DNS manager I had created a AAAA record for the IPv6 address. But when I run dig -6 -t AAAA mydomain.com from the command line, it times out. The record clearly exists in the DNS manager, so I think something might be wrong on the Linode side.
"dig -6" talks to your resolver using IPv6.
What protocol you're using to send DNS queries, and whether you're querying for A or AAAA records, are orthogonal.
Do you have a working IPv6 resolver? Does something like "dig -6 example.com" work?
Does "dig -t AAAA mydomain.com" work?
What's your real domain/hostname?
dig -6 example.com times out.
dig -t AAAA example.com does work -- it returns an ANSWER SECTION with the domain mapped to the IPv6 address. See below.
Also, if I do an external AAAA lookup (e.g. from mxtoolbox.com) it states the DNS is not found.
root@example:/etc# dig -t AAAA example.com
; <<>> DiG 9.11.3-1ubuntu1.11-Ubuntu <<>> -t AAAA example.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 29589
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;example.com. IN AAAA
;; ANSWER SECTION:
example.com. 0 IN AAAA [IPv6 ADDRESS]
;; Query time: 0 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: Mon Jan 17 00:39:59 UTC 2022
;; MSG SIZE rcvd: 86
dig -6 example.comtimes out.
dig -t AAAA example.comdoes work -- it returns an ANSWER SECTION with the domain mapped to the IPv6 address. See below.
Also, if I do an external AAAA lookup (e.g. from mxtoolbox.com) it states the DNS is not found
Both of these symptoms support the diagnosis that your DNS is not set up properly. Did you point your registrar to Linode's name servers?
-- sw
Argh…
Yes, the problem was the DNS. We were handling the DNS with the domain registrar, not with Linode. There was just enough working on the Linode side that I thought the problem was there. It's resolved now. Thanks for the help.