In a wide area network (WAN) how would you troubleshoot an issue with the domain name sytem?

To troubleshoot a Domain Name System (DNS) issue in a wide area network (WAN), start by verifying the DNS configuration on the client devices, ensuring they are pointing to the correct DNS servers. Use tools like nslookup or dig to check DNS resolution for specific domain names and identify any errors. Additionally, inspect the DNS server logs for any signs of failure or misconfiguration, and ensure that network connectivity between the client and DNS servers is intact. Finally, check for any firewall rules or security settings that might be blocking DNS traffic.