check_http adding domain name to fqdn ?

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check_http adding domain name to fqdn ?

Postby jlom » Mon May 21, 2018 9:25 am

Hi,

I have a weird problem I can't figure out why this would be happening.

I Have a site being checked with check_http every once in a while I am getting my domain added to the end of the FQDN.
[2018-05-21T08:17:10] SERVICE ALERT: name.domain.com;HTTP-Port80-slower-site;CRITICAL;SOFT;1;Temporary failure in name resolution

Here is the log from my DNS server which is how I know this is happening


2018-05-21T08:17:10-04:00 dns-1.net.domain.com named[15326]: client 123.123.123.1#56289 (commencement.domain.com.domain.com): query: commencement.domain.com.domain.com IN AAAA + (123.123.1.1)
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Re: check_http adding domain name to fqdn ?

Postby mcapra » Tue May 22, 2018 8:45 am

Which version of check_http are you using? This should provide that information:

Code: Select all
/path/to/check_http --version


Which operating system and version of that operating system is doing the executing of check_http?

I'm pretty sure this is a general getaddrinfo failure that's happening here:
https://github.com/nagios-plugins/nagios-plugins/blob/60dad1471baba4d8af4527ecb1a2b66a7c6d8eed/plugins/netutils.c#L207

Which would indicate this is a DNS related problem, possibly NXDOMAIN hijacking from some malicious actor (there's not much to gain, frankly), competing resolvers, or some other misconfigured aspect of name resolution on the machine itself.

I'm not totally convinced this is a check_http specific problem, but we'll do our due diligence.
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Re: check_http adding domain name to fqdn ?

Postby cdienger » Tue May 22, 2018 1:07 pm

+1 on a dns resolution issue. If a hostname cannot be resolved, it will try again but tack on the domain name found in /etc/resolv.conf.
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