NAME | SYNOPSIS | DESCRIPTION | OPERATION | COMMAND LINE | ATTRIBUTES | SEE ALSO | AUTHOR
The Internet Software Consortium DHCP Relay Agent, dhcrelay, provides a means for relaying DHCP and BOOTP requests from a subnet with no direct DHCP--server connection to one or more DHCP servers on other subnets.
The DHCP Relay Agent listens for DHCP requests on all interfaces attached to a host, unless one or more interfaces are specified on the command line by using the -i flag.
When a query is received, dhcrelay forwards it to the list of DHCP servers specified on the command line. When a reply is received, it is broadcast or unicast to the network from which the original request came.
It is possible to specify a set of interfaces on which dhcrelay will listen. Therefore, if dhcrelay is connected through one interface to a network on which there is no DHCP server, but is also connected on another interface to a network on which there is a DHCP server, it will not relay DHCP and BOOTP requests from the network on which the server exists to that server. dhcrelay will assume that clients on the network where there is a DHCP server will automatically connect to that server.
The names of the network interfaces that dhcrelay should attempt to configure may be specified on the command line using the -i option. If no interface names are specified on the command line, dhcrelay will identify all network interfaces, elimininating non-broadcast interfaces if possible, and attempt to configure each interface.
If dhcrelay listens and transmits on a port other than the standard (port 67), the -p flag may used. It should be followed by the udp port number that dhcrelay should use. This is mainly useful for debugging purposes. If the -p flag is specified, the relay agent will transmit responses to clients at a port number that is one greater than the one specified, namely, if you specify -p 67, the relay agent will listen on port 67 and transmit to port 68. Transmissions to servers will be sent to the same port number that it specified in the -p flag.
dhcrelay normally prints its network configuration on startup. This can be annoying in a system startup script. Use the -q flag to disable this behavior.
The name of at least one DHCP server to which DHCP and BOOTP requests are to be relayed must be specified on the command line.
See attributes(5) for descriptions of the following attributes:
ATTRIBUTE TYPE | ATTRIBUTE VALUE |
---|---|
Interface Stability | Evolving |
dhcpd(1M), RFC2132, RFC2131.
dhcrelay was originally written by Ted Lemon <mellon@vix.com> under a contract with Vixie Labs. Funding for this project was provided by the Internet Software Consortium. Information about the Internet Software Consortium can be found at http://www.isc.org/isc. To learn more about Vixie Enterprises, see http://www.vix.com.
NAME | SYNOPSIS | DESCRIPTION | OPERATION | COMMAND LINE | ATTRIBUTES | SEE ALSO | AUTHOR