6 Core Network Services Free Online FlashCards

What does DHCP provide to network clients?

DHCP leases clients IP addresses and can provide settings such as the subnet mask, default gateway, DNS server, and lease duration.

How should a DHCP pool relate to the client subnet?

A DHCP scope or pool must match the clients’ subnet so they receive appropriate addresses and configuration.

Why exclude infrastructure addresses from a DHCP range?

Exclude the gateway, servers, and other statically addressed devices from the dynamic range to prevent address conflicts.

How can clients reach a DHCP server on another subnet?

DHCP broadcasts do not normally cross routers. Configure a relay, commonly with ip helper-address on the client-facing router interface.

What client settings should you verify after renewing a DHCP lease?

Check the client’s assigned IP address, subnet mask, gateway, and DNS server; confirm they match the intended subnet and configuration.

How is DNS organized and used to resolve names?

DNS is a distributed, hierarchical database. Servers publish records in zones, while client resolvers query servers and can cache answers.

What do DNS records A, AAAA, CNAME, and PTR represent?

A maps a name to an IPv4 address; AAAA maps a name to an IPv6 address; CNAME identifies an alias; PTR maps an address to a name.

Does configuring a router’s upstream DNS server make it authoritative?

Configuring a router to use an upstream DNS server makes it a resolver; it does not make it an authoritative DNS server. Authoritative records belong on the organization’s DNS platform.

How can a direct DNS-server query help troubleshoot name resolution?

Query the configured DNS server directly, for example with nslookup files.example.test 192.168.10.10. This helps distinguish a server or record problem from an incorrect client resolver setting.

How are NAT and PAT related?

NAT changes IP addresses as traffic passes between networks. PAT, also called NAT overload, lets multiple inside IPv4 hosts share one outside address.

How does PAT distinguish connections sharing one outside address?

PAT distinguishes multiple connections using transport-layer ports, allowing multiple inside IPv4 hosts to share one outside address.

Can NAT replace a firewall or access-control policy?

No. NAT translates addresses, but it is not a substitute for a firewall or an access-control policy.