We have nagios running but can't reach a different network directly. I would like to use Distributed Nagios eXecutor on a dmz server to execute checks in stead of building a new Nagios server and working with passive checks etc.
Does anybody know if this is possible to only do checks for some servers through a DNX server?
The DNX server configuration doesn't allow you to specify which checks should be ran through DNX workers... What it does allow you to do is specify the checks that should be handled locally and not be sent to the message queue for DNX workers to process.
You could potentially use this if all your checks you want to run locally match a common regular expression that does not match the ones you want to be ran remotely. By default DNX server will schedule all checks to be ran by DNX so this could allow you to short circuit this.
That said I would hazard that DNX is not the right tool for what you're attempting and might be better suited setting up a distributed poller that handles all the checks for the remote network and passes the results back to this Nagios instance. DNX was more designed to distribute the actually polling load without having to run multiple Nagios instances as the DNX work only needs to have the plugins.
I have a Nagios deployment with a single central server and then Nagios polling instances in 3 data centers that report back to it. We're looking to use DNX in each data center from the polling instances to be able to add DNX workers to maintain the ability to execute all the checks within a certain period of time. As more checks are added we can add additional DNX workers and when the number of checks decline reduce the number of DNX workers. In this each polling instance only receives the configuration for those checks it is expected to actively check and the central server is setup to accept these results as passive checks.