DHCP: Portability
n Initiate connectivity to Internet by DHCP request
n Once initial IP address has been obtained, start all
servers/demons, etc.
n Suppose host detects movement: re-issue new
DHCP request to validate current IP address
if okay, proceed
if new address needed, we have a problem
n new IP address will not work with existing connections
shut down and reboot machine
n since no other node knows new IP address, MH has to initiate
all requests
alternative: allow DNS updates, which takes time and introduces
new security problem