Zabbix is used to monitor Certificates of external services.

Therefore we use the certificates plugin key: web.certificate.get[<website_DNS_name>] which is already working fine for internal usecases as long as no Proxy is in between.

For resolving external URLs like www.google.com, a proxy whitelisting rule needs to be set.

Unfortunately the Agent2 plugin resolves the given URL and converts it to an IP address. A second call then is made using the IP address instead of the URL for which the proxy whitelisting was created resulting in following error:

This timeout happens because the Agent2 plugin suddenly switches over to IP address and tries to do another TCP dial which is resulting in a timeout.

It is necessary to either stick just one TCP dial in coding or completely stick to the URL if no specific IP is given.