Installing, Configuring, and Troubleshooting Network Services
Operating the services
Where domain 3 plans services, this domain runs them. Be comfortable with DNS record types (A, AAAA, CNAME, MX, PTR, SRV, TXT), zone types (primary, secondary, stub, forward/reverse), scavenging and ageing, and the difference between recursion and forwarding. For DHCP, know scope creation, exclusions, reservations, options at server/scope/reservation level and their precedence, and how to read a lease. For remote access, know VPN tunnel types, authentication methods, and split versus full tunnelling.
Diagnosing service faults
Use the right tool: nslookup/dig for resolution path and record content, ipconfig /flushdns and /registerdns for client cache and registration, DHCP server logs and lease databases for address faults, and event logs for service start failures. Understand that a client can resolve a name correctly and still fail to connect if the record points at the wrong address - verify the record, not just the query.
Traps
Questions often confuse forward and reverse zones, or assume a CNAME can exist at the zone apex alongside other records (it cannot). DHCP option precedence is a frequent trap: scope-level options override server-level ones, and reservation-level options override both. Another trap is blaming DNS for a failure that is actually a firewall rule blocking the port.
Worked example
Users can reach an intranet site by IP but not by name; nslookup against the internal server returns the correct address, but the client's configured DNS is an external resolver. The fault is client DNS configuration or DHCP option 006, not the zone.
Also know
Service restart versus reload, replication scope for DNS zones in AD-integrated environments, and auditing of administrative changes.