Handle DNS Failures

[highvolt-dev]

Handle DNS failures in a more explicit way.

Pinging an IP address (e.g. 1.1.1.1 or 8.8.8.8) can indicate whether there is network connectivity regardless of DNS functionality.

Likewise, more explicitly checking that DNS resolution is working may be a desirable but separate health check.

[SteveEbey73742]

using -H with either IP or domain name should work in current versions