periodic could not resolve hostname - sr-users

28 Sep 2023

Aloha,

I'm experiencing this internal DNS problem with Kamailio, can't seem to
figure out what's causing it. Maybe someone can help.

Essentially, from time to time (one or two times a day) this situation
happens, starting with logs:

linux kamailio[773]: ERROR: uac [uac_reg.c:1163]: uac_reg_send(): failed to
send request for [some-uuid]
linux kamailio[773]: ERROR: <core> [core/resolve.c:1730]:
sip_hostport2su(): could not resolve hostname: "my.domain.net"
linux kamailio[773]: ERROR: tm [ut.h:309]: uri2dst2(): failed to resolve "
my.domain.net"
linux kamailio[773]: ERROR: tm [uac.c:480]: t_uac_prepare(): no socket found

# Do a Kamailio internal DNS lookup, no results found???
root@linux:~# kamcmd dns.lookup a my.domain.net
error: 400 - Not found

# Do a system DNS lookup. All good.
root@linux:~# dig my.domain.net
;; QUESTION SECTION:
;my.domain.net. IN A
;; ANSWER SECTION:
my.domain.net. 18000 IN A 192.168.0.1

# Delete internal Kamailio DNS record
root@linux:~# kamcmd dns.delete_a my.domain.net

# Lookup again right away. It's there, problem fixed. Why??
root@linux:~# kamcmd dns.lookup a my.domain.net
{
  name: my.domain.net
  type: A
  size_bytes: 120
  reference_counter: 2
  permanent: no
  expires: 7674
  last_used: 0
  negative_entry: no
  records: {
      {
         rr_idx: 0
         rr_ip: 192.168.0.1
         rr_permanent: no
         rr_expires: 7674
      }
   }
}