From the known errors page:

DNS error reported for network tests

The xymonnet network tester uses the built-in ARES library for DNS lookups. There have been reports that this library fails on some systems; one confirmed case is on "OSF1 V5.1". So if you suddenly get a lot of failed network tests that report "DNS error", try running xymonnet with the "--no-ares" option to use the standard DNS lookups instead.

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On 5/4/2011 at 11:48 PM, in message <BANLkTinwG9V6-PvMXvLz=aYEVXj5GMWOgA at mail.gmail.com>, Raul GN <ragonlan at gmail.com> wrote: Hi, Since I installed version 4.3 (previous version may have same issue) DNS timeout stopped working. In Task.cfg I put this line:

CMD xymonnet --report --ping --checkresponse --timeout=10 --dns-timeout=15

But dns-timeout didn't solve the issue.

When I put a host that doesn't response to DNS, time-out is too large: Wed May 4 16:03:59 2011 dns NOT ok Service dns on HS-755 is not OK : Service unavailable Timeout Seconds: 178.169

If I remove dns-timeout parameter DNS check time is even greater:

Service dns on HS-755 is not OK : Service unavailable

Timeout

Seconds: 356.336

With DNS test enabled: <<

TIME SPENT Event Start time
Duration xymonnet startup 1357697.287237
- Service definitions loaded 1357697.287887
0.000650 Tests loaded 1357697.293270
0.005382 DNS lookups completed 1357699.442598
2.149328 Test engine setup completed 1357699.445198
0.002600 TCP tests completed 1357711.442436
11.997237 PING test completed (108 hosts) 1357719.107813
7.665377 PING test results sent 1357719.108279
0.000465 Test result collection completed 1357719.108485
0.000205 LDAP test engine setup completed 1357719.108485
0.000000 LDAP tests executed 1357719.108486
0.000000 LDAP tests result collection completed 1357719.108486
0.000000 DNS tests executed 1357897.279645
178.171159 Test results transmitted 1357897.281396
0.001751 xymonnet completed 1357897.282446
0.001049 TIME TOTAL
199.995208

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Without DNS test:

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TIME SPENT Event Start time
Duration xymonnet startup 64910.045082
- Service definitions loaded 64910.045765
0.000682 Tests loaded 64910.051131
0.005365 DNS lookups completed 64910.055655
0.004524 Test engine setup completed 64910.058453
0.002797 TCP tests completed 64911.034675
0.976221 PING test completed (105 hosts) 64912.167164
1.132489 PING test results sent 64912.168239
0.001074 Test result collection completed 64912.168467
0.000227 LDAP test engine setup completed 64912.168467
0.000000 LDAP tests executed 64912.168468
0.000000 LDAP tests result collection completed 64912.168468
0.000000 DNS tests executed 64912.177910
0.009441 Test results transmitted 64912.179840
0.001930 xymonnet completed 64912.181299
0.001459 TIME TOTAL
2.136217

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Does anyone know how to fix it? If I put many DNS test failures the whole xymon get purple because xymonnet don't do DNS test in parallel but in serial (one after other).

thank for you time,