Nagios Support Forum

1. Can the email template be modified to include the hostnames of the "Not Sending" hosts?

2. Once Nagios LS again starts receiving logs from a formerly "Not Sending" host, does the logging start fresh from that point or does the logs catch up to provide the log server with the previously unlogged data?

Sometimes I see a fair number of "Not Sending" hosts which should otherwise be sending logs?

1. I believe this should work with the %uniquehosts% macro and using freshness alerts. Freshness alerts are are relatively new(2.1.0) - https://assets.nagios.com/downloads/nag ... Server.pdf so you may need to upgrade.

2. This depends on the client that is sending the logs. NLS will accept mostly anything that a client sends and it would be up to the client to make sure that log are sent. You can help avoid lost logs by making sure the clients use TCP instead of UDP to send logs.

3. I would first check on the client side to make sure the sending process is still working. A tcpdump on the NLS command line can also verify if the data is getting to it: