check_dyndns

This plugin determines the current external address (by checking with checkip.dyndns.org). Then it finds the address known to DNS. If they do not match, there are two possibilites:

1. Just report the problem (as CRITICAL)
2. Correct the problem (if credentials to do so are given) and return as WARNING state.

Dyndns says not to query their checkip-host more often than every ten minutes, therefore a cache file is used to store the last known result and a new query is only done, if the ten minutes have passed (very useful, if you have multiple hostnames registered with dyndns - otherwise just increase the check_interval in nagios).

- Usage: check_dyndns host-to-check [dyndns-credentials]
- host-to-check - is the host (e.g. mylovelyhost@dyndns.org)
- dyndns-credentials - if present, use these to update the address (format: user:password)

Notes:

* DO NOT put the credentials in the object descriptions or commands! Consider using a $USERxx$ macro for this purpose.
* If using a proxy server to access the internet, you can set it in the script at the very beginning (CurlHttpProxy=)
* The location of the cache-file can also be changed there (LastCheckFile=)