Users Guide

Layer 3 Routing Commands 1509
configuration for the destination UDP port. If so, the relay agent unicasts the
packet to the configured server IP addresses. Otherwise the packet is not
relayed.
The relay agent only relays packets that meet the following conditions:
• The destination MAC address must be the all-ones broadcast address
(FF:FF:FF:FF:FF:FF).
• The destination IP address must be the IPv4 broadcast address
(255.255.255.255) or a directed broadcast address for the receiving
interface.
• The IP time-to-live (TTL) must be greater than 1.
• The protocol field in the IP header must be UDP (17).
• The destination UDP port must match a configured relay entry or an entry
in Table 6-1.
DHCP relay cannot be independently enabled or disabled globally. Only IP
helper can be enabled or disabled globally. Enabling IP helper enables DHCP
relay.
ip dhcp relay maxhopcount
Use the ip dhcp relay maxhopcount command in Global Configuration mode
to configure the maximum allowable relay agent hops for BootP/DHCP Relay
on the system. Use the no form of the command to set the maximum hop
count to the default value.
Syntax
ip dhcp relay maxhopcount integer
no ip dhcp relay maxhopcount
•
integer — Maximum allowable relay agent hops for BootP/DHCP Relay on
the system. (Range: 1-16)
Default Configuration
The default integer configuration is 4.