I've got several PCs, virtual and bare metal, that run clients of the collectd daemon and report their statuses to the monitoring server.
One of those PCs is incorrectly configured and reports localhost as its name.
How can I find its IP address?
The simple answer would be to run a tcpdump on the port used for collectd (port 2003 for example) and check the different IPs. run ssh and pipe directly to the config file to see which one has the wrong host set:
echo "sudo nano /etc/collectd/collectd.conf | grep "Host" | ssh user@IP