Day 50 Flashcards - DHCP Snooping

Enable DHCP Snooping on the switch:SW1(config)# […]

ip dhcp snooping

Enable DHCP Snooping on a VLAN:SW1(config)# […]

ip dhcp snooping vlan vlan-number

Enable errdisable recovery for DHCP rate limiting violations:SW1(config)# […]

errdisable recovery cause dhcp-rate-limit

Configure the DHCP snooping-enabled switch to not add option 82 to DHCP messages:SW1(config)# […]

no ip dhcp snooping information option

Configure a DHCP snooping trusted port:SW1(config-if)# […]

ip dhcp snooping trust

Limit the rate that DHCP messages are allowed on a DHCP snooping enabled interface:SW1(config-if)# […]

ip dhcp snooping limit rate packets-per-second

Show the DHCP snooping binding table:SW1# […]

show ip dhcp snooping binding

When DHCP snooping is enabled, all interfaces are [trusted/untrusted] by default.

untrusted

DHCP Server or DHCP Client message?OFFER

Server

DHCP Server or DHCP Client message?ACK

Server

DHCP Server or DHCP Client message?NAK

Server

DHCP Server or DHCP Client message?DISCOVER

Client

DHCP Server or DHCP Client message?REQUEST

Client

DHCP Server or DHCP Client message?RELEASE

Client

DHCP Server or DHCP Client message?DECLINE

Client

DHCP snooping untrusted port:If a DHCP […] message is received, discard it with no further checks.

Server

DHCP snooping untrusted port:If a DHCP […] message is received, inspect the message to determine if it should be forwarded or discarded.

client

DHCP Snooping: When a client successfully leases an IP address from a server, create a new entry in the […]

DHCP Snooping Binding Table

If DHCP snooping rate-limiting is configured and the rate is exceeded, what happens?

The interface is err-disabled

DHCP Option […] is also known as the DHCP Relay Agent Information Option.

82

By default, Cisco switches will drop DHCP messages with Option 82 that are received on an […] port.

untrusted