Basically, as near as I can tell, dnscache is refusing dns requests.
I may be wrong in this assumption, but I've reached the end of my
knowledge, and the end of any pertinent list archives I've been able
to find on the subject. I turn to the list for further information.
Background information:
The server is running tinydns on 65.40.71.210 and dnscache on
65.40.71.211. This is installed on "4.9-RELEASE FreeBSD 4.9-RELEASE
#0:" and has been operating for several years now without problems
(even after a reboot). This morning, I realized it wasn't responding
to requests. The only event I can think of that happened to the
server was two weeks ago -- while working in the NOC, the server was
unplugged accidentally (loose power cord) and hard-rebooted. I don't
see how this affected dnscache (and supposedly only that program), but
it's the only action taken on the server in recent months (uptime 14
days).
I checked and dnscache is running. It also continuously append to the
log in "log/main/current". It appears to be active and doing stuff.
Every so often, it runs through a loop of cached entries. I recreated
a snippet here:
-------
@40000000459af9f401ef52bc query 25570 412847d7:0e11:6f1f 12
215.71.40.65.in-addr.arpa.
@40000000459af9f401f3e69c cached 12 215.71.40.65.in-addr.arpa.
@40000000459af9f401f3fe0c sent 25570 90
@40000000459af9f40214e004 query 25571 412847d7:06c5:6f20 1 sql.thepcmd.info.
@40000000459af9f40218eb2c cached ns thepcmd.info. ns1.lightsp.com.
@40000000459af9f40219029c cached ns thepcmd.info. ns0.lightsp.com.
@40000000459af9f402191a0c cached 1 ns1.lightsp.com.
@40000000459af9f40219317c cached 1 ns0.lightsp.com.
@40000000459af9f402194504 tx 0 1 sql.thepcmd.info. thepcmd.info.
412847d4 412847d2
@40000000459af9f41f53dbfc servfail sql.thepcmd.info. input/output error
@40000000459af9f41f589ad4 sent 24916 34
@40000000459af9f432c0f92c query 25572 412847d7:0568:514c 16
235.20.136.85.sbl.spamhaus.org.
@40000000459af9f432cb22bc cached ns sbl.spamhaus.org. y.ns.spamhaus.org.
@40000000459af9f432cb3e14 cached ns sbl.spamhaus.org. x.ns.spamhaus.org.
@40000000459af9f432cb5584 cached ns sbl.spamhaus.org. w.ns.spamhaus.org.
-------
Immediately after restarting dnscache, I get a timeout. After a few
seconds, I get connection refused. Netstat -nl shows dnscache
listening on port 53. It appears as if dnscache itself is blocking
access (I have made sure no firewall rules are running). Plus, the
transition from timeout to refused is pretty telling.
root@primus_dnscache 0%: ls -1 root/ip
0
0.0.0.0
127.0.0.1
65.40.71
65.40.71.208
65.40.71.210
65.40.71.211
Everything had been working with 0.0.0.0 listed. I specifically added
the additional ip addresses during the troubleshooting process.
root@primus_ip 0%: sudo /usr/local/etc/rc.d/services.sh restart
Restarting services: axfrdns dnscache tinydns.
root@primus_ip 0%: dig google.com @65.40.71.211
; <<>> DiG 8.3 <<>> google.com @65.40.71.211
; (1 server found)
;; res options: init recurs defnam dnsrch
;; res_nsend: Operation timed out
root@primus_ip 0%: dig google.com @65.40.71.211
; <<>> DiG 8.3 <<>> google.com @65.40.71.211
; (1 server found)
;; res options: init recurs defnam dnsrch
;; res_nsend: Connection refused
root@primus_ip 0%: dig google.com @65.40.71.211
; <<>> DiG 8.3 <<>> google.com @65.40.71.211
; (1 server found)
;; res options: init recurs defnam dnsrch
;; res_nsend: Connection refused
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