Standard Nagios Plugins 1.4.9 and IPv6 problem?

[Ton Voon]

On 20 Sep 2007, at 19:36, Frost, Mark {PBG} wrote:

> We're looking to changes the modules file for this box to prevent any
> component of IPv6 being loaded, but I'm still not convinced that will
> dissuade the plugins from going on their merry way.

Sorry to jump in late on this thread.

In the plugins code, the is_hostname routine tries to verify if the  
hostname is valid and I think this is through the resolver libraries,  
so will use DNS (regardless of OS caching). I think more recent  
resolver libraries will try ipv6 resolution before ipv4, which is  
beyond the scope of the plugins.

As some people have already pointed out, checking the validity of the  
hostname is redundant. The better approach is to just make the call  
with the hostname specified on the command line and catch any errors.

I believe this is why your DNS servers see multiple calls for the  
same hostname from a single plugin invocation.

While removing the is_hostname calls is not too difficult, making  
sure that an appropriate error is propagated into the plugin output  
could be quite time-consuming.

Ton

http://www.altinity.com
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Skype: tonvoon




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