Checking DNS:

dig

1. What’s the IP address for a domain?

Note: ping won’t necessarily work if ICMPpackets are refused but this does the job:

dig +short <domain name>

2. query a specific nameserver

e.g. your DNS might be OK with your internal DNS servers but not have propagated to public DNS servers like Google’s 8.8.8.8.

dig@<nameserver> <domain.com>

nslookup