DHCP & Multilayer Switches

Question 1

Briefly describe the DHCP handshake.

Answer 1

1. Host sends discovery broadcast.
2. Server replies with offer broadcast.
3. Host replies with a request broadcast.
4. Server responds with an ACK broadcast.

Question 2

What is a requirement for each subnet that a Cisco device is handing out?

Answer 2

The device must have an IP in that subnet on either a SVI, sub interface, or physical interface.

Question 3

On Cisco devices, how are DHCP exclusions configured?

Answer 3

Manually, via the global-config context.

Question 4

What IPs must be excluded in a DHCP range?

Answer 4

All that you need, including the IP residing on the Cisco device.

Question 5

Briefly describe how to configure a DHCP pool.

Answer 5

1. Create the pool with the “ip dhcp pool” command.
2. Set your range with the “network” command.
3. Configure your default router.
4. Configure your DNS server.
5. Configure your domain name.
6. Configure your lease time.

Question 6

What is a DHCP helper address?

Answer 6

The address of a DHCP server, configured on a SVI, sub interface, or physical interface. It relays DHCP messages to out-of-network servers.

Question 7

How many DHCP helper addresses can be configured on an interface?

Answer 7

As many as you want. The first one will be used, if it’s unreachable the device will move to the next one in the list.

Question 8

Can you configure static IPs in a Cisco DHCP pool?

Answer 8

Yes, with the “host” and “client-identifier” commands.