ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/0/0 dhcp

[Wizard4777]

what does the dhcp command in the following line "ip route 0.0.0.0 0.0.0.0 GigabitEthernet0/0/0 dhcp" do?

[MHM Cisco World · Accepted solution]

Defualt route  use two 

1- egress 

2- next  hop 

Next  hop is always change since you use dhcp so instead of harcoded next hop we add "dhcp" keyword' and this make route auto add next hop receive from ISP via dhcp

MHM

[Joseph W. Doherty]

@MHM Cisco World correctly answers the "what" the command does but possibly the significance of "why" might not be appreciated since just using the egress interface may work too.  Using a next hop address avoids using ARP and loading up an ARP cache with every egress destination address.  (Occasionally a very large ARP cache can crash a router.)