A method and system is provided to send and receive Dynamic Host
Configuration Protocol ("DHCP") messages in a data-over-cable system via a
route with one or more routers. The routers may apply one or more
different protocol filters to DHCP messages, such as filtering out DHCP
messages with a "Martian" Internet Protocol ("IP") address (e.g., 0.0.0.0)
and other characteristics. The Martian IP address is commonly used as an
initial IP address in a DHCP initialization sequence but is often filtered
out by routers as an invalid IP address. DHCP messages are received by a
first protocol agent from a first User Datagram Protocol ("UDP") port. The
first UDP port is used by DHCP servers and network devices such as cable
modems and customer premise equipment to send and receive DHCP messages
via a route that may apply one or more DCHP filters. The first protocol
agent sends the DHCP messages to a second protocol agent on a second UDP
port via a route that does not apply filters to the DHCP messages. The
first protocol agent receives DHCP messages from the second protocol agent
on the second UDP port. The first protocol agent sends messages back to a
DHCP protocol server or network device such as a cable modem on the first
UDP port. The protocol agent allows DHCP messaging to be seamlessly used
in a data-over-cable system with routers that apply a variety of protocol
filters to DHCP messages.
