[asterisk-users] Strange problem with Asterisk 1.8.9.3

[Dereck D]

Hello List.
Last month i started to face a strange issue on an asterisk server
1.8.9.3 built on Centos 5.3 x86_64 dedicated server.
out of the blue UDP stops responding .. and keep getting the following output:

---------------------------------- Opening message for the problem
--------------------------------------------------
[Mar 21 09:57:04] ERROR[6748] netsock2.c:
getaddrinfo("pbx2.server.com", "(null)", ...): Temporary failure in
name resolution
[Mar 21 09:57:04] WARNING[6748] acl.c: Unable to lookup 'pbx2.server.com'
----------------------------------------------------------------THEN
-------------------------------------------------------------
[Mar 21 09:57:04] NOTICE[6748] chan_sip.c: Peer 'YYYY' is now
UNREACHABLE!  Last qualify: 10
[Mar 21 09:57:04] NOTICE[6748] chan_sip.c: Peer 'C1045' is now
UNREACHABLE!  Last qualify: 140
[Mar 21 09:57:04] NOTICE[6748] chan_sip.c: Peer 'XXXX' is now
UNREACHABLE!  Last qualify: 33
[Mar 21 09:57:15] NOTICE[6748] chan_sip.c:    -- Registration for
'8885008 at pbx2.server.com' timed out, trying again (Attempt #3)
[Mar 21 09:57:21] NOTICE[6748] chan_sip.c: Peer 'C3000' is now
UNREACHABLE!  Last qualify: 87
[Mar 21 09:57:21] NOTICE[6748] chan_sip.c: Peer 'C5005' is now
UNREACHABLE!  Last qualify: 241
[Mar 21 09:57:21] NOTICE[6748] chan_sip.c: Peer 'C1071' is now
UNREACHABLE!  Last qualify: 117
[Mar 21 09:57:21] NOTICE[6748] chan_sip.c: Peer 'C1070' is now
UNREACHABLE!  Last qualify: 115
[Mar 21 09:57:21] NOTICE[6748] chan_sip.c: Peer 'C1077' is now
UNREACHABLE!  Last qualify: 101
[Mar 21 09:57:21] NOTICE[6748] chan_sip.c: Peer 'C1073' is now
UNREACHABLE!  Last qualify: 96
[Mar 21 09:57:21] NOTICE[6748] chan_sip.c: Peer 'C1047' is now
UNREACHABLE!  Last qualify: 132
[Mar 21 09:57:21] NOTICE[6748] chan_sip.c: Peer 'C1072' is now
UNREACHABLE!  Last qualify: 138
[Mar 21 09:57:21] NOTICE[6748] chan_sip.c: Peer 'C1042' is now
UNREACHABLE!  Last qualify: 158
[Mar 21 09:57:21] NOTICE[6748] chan_sip.c: Peer 'C5006' is now
UNREACHABLE!  Last qualify: 267
[Mar 21 09:57:21] NOTICE[6748] chan_sip.c: Peer 'C1053' is now
UNREACHABLE!  Last qualify: 136
[Mar 21 09:57:41] NOTICE[6748] chan_sip.c:    -- Registration for
'8885005 at pbx2.server.com' timed out, trying again (Attempt #3)
[Mar 21 09:57:41] NOTICE[6748] chan_sip.c: Peer 'ipkall1' is now
UNREACHABLE!  Last qualify: 168
[Mar 21 09:57:41] NOTICE[6748] chan_sip.c: Peer 'C1078' is now
UNREACHABLE!  Last qualify: 141
[Mar 21 09:57:41] NOTICE[6748] chan_sip.c: Peer 'C1051' is now
UNREACHABLE!  Last qualify: 139
[Mar 21 09:57:41] NOTICE[6748] chan_sip.c: Peer 'C1046' is now
UNREACHABLE!  Last qualify: 157
[Mar 21 09:57:41] NOTICE[6748] chan_sip.c: Peer 'C1076' is now
UNREACHABLE!  Last qualify: 116


this problem kept repeating randomly two or three times a day causing
me losses. and then i migrated to another Centos 6x x86_64 dedicated
server same asterisk version.
everything returns to normal if i reboot the server.  for a moment i
thought i wasn't even able to nslookup but i could wget or yum or do
other stuff..although i have my iptables disabled for a the last week
for testing purposes.
what i did today after the problem is:
bindaddress: set to server IPv4 address instead of defaulting.
disabled IPv6 from the server.


any suggestions to what is causing this issue?