Moving to a IPv4 only server

[Julien Salort]

Hello,

I am sorry if this is a FAQ. I haven't been able to find the answer.

I used to have bind9 running on a server with both IPv4 and IPv6. This 
server has failed unfortunately, and I am setting up replacement using 
the last backup of the failed server. The new server happens to have 
IPv4 address only, unfortunately. Both the old and the new server are 
running Ubuntu 22 if that matters.

I copied /etc/bind directory from the backup to the new server.

Authoritative zones work fine. It also transfers successfully to the 
slaves when I make changes in the zones.

However, I can't get the recursion to work. I originally had a lot of 
"network unreachable" with IPv6 addresses. So I figured I should start 
bind with -4 option. Now, I no longer have the "network unreachable" 
errors in the log, but it is still unable to recurse.

For example:

dig www.google.com @127.0.0.1

;; communications error to 127.0.0.1#53: timed out
;; communications error to 127.0.0.1#53: timed out

; <<>> DiG 9.18.12-0ubuntu0.22.04.2-Ubuntu <<>> www.google.com @127.0.0.1
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 35198
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
; COOKIE: a497120ee47312be0100000064dfccb2ba16350e188a7bc4 (good)
;; QUESTION SECTION:
;www.google.com.            IN    A

;; Query time: 1988 msec
;; SERVER: 127.0.0.1#53(127.0.0.1) (UDP)
;; WHEN: Fri Aug 18 19:55:30 UTC 2023
;; MSG SIZE  rcvd: 71


And in the log file:

Aug 18 19:55:23 vpsl named[3183]: client @0x7f8a4c0152f8 127.0.0.1#33163 
(www.google.com): query: www.google.com IN A +E(0)K (127.0.0.1)
Aug 18 19:55:28 vpsl named[3183]: resolver priming query complete: timed 
out
Aug 18 19:55:28 vpsl named[3183]: client @0x7f8a5420b6f8 127.0.0.1#43890 
(www.google.com): query: www.google.com IN A +E(0)K (127.0.0.1)
Aug 18 19:55:30 vpsl named[3183]: shut down hung fetch while resolving 
'www.google.com/A'
Aug 18 19:55:30 vpsl named[3183]: client @0x7f8a54213b58 127.0.0.1#46373 
(www.google.com): query failed (operation canceled) for 
www.google.com/IN/A at query.c:7794
Aug 18 19:55:30 vpsl named[3183]: client @0x7f8a5420b6f8 127.0.0.1#43890 
(www.google.com): query failed (operation canceled) for 
www.google.com/IN/A at query.c:7794
Aug 18 19:55:30 vpsl named[3183]: client @0x7f8a4c0152f8 127.0.0.1#33163 
(www.google.com): query failed (operation canceled) for 
www.google.com/IN/A at query.c:7794
Aug 18 19:55:38 vpsl named[3183]: resolver priming query complete: timed 
out


It feels like there are some root server addresses with IPv6 address 
that it can't use, but I have no clue where these addresses are and how 
to replace them with their IPv4 counterparts.


Thanks for any clue,


Julien