DHCP(9)                 XR32 REFERENCE MANUAL                 2/2/2013

NAME
        DHCP -- Dynamic Host Configuration Protocol.

DESCRIPTION
        The acronym DHCP stands for Dynamic Host Configuration
        Protocol.  This is a client-server based protocol which allows
        clients on a TCP/IP network to obtain their configuration
        parameters from a server.

        The protocol supports the transfer of a wide range of
        configuration parameters such as the client's IP address,
        netmask, DNS and gateway addresses, plus TCP/IP parameters
        such as MSS, but is most commonly used to allocate dynamic IP
        addresses to clients.

        IP addresses are "leased" to clients for a period of time,
        after which the client must renew the lease.  Servers
        generally attempt to re-assign the same IP address to the same
        client.


        DHCP in Xrouter
        ~~~~~~~~~~~~~~~
        XR32 includes a DHCP client, and a DHCP server may be
        included in future, if the need arises.  The full range of
        configuration options is not supported, since in most XR32
        application scenarios they are not required.  The options
        currently supported are client's IP address and lease time,
        DNS and gateway IP addresses.

        The DHCP client is available only on Ethernet interfaces
        which are using the NdisXpkt driver.  Lease negotiation and
        renewal are completely automatic, and the sysop need not be
        concerned with the process.


        Do you need DHCP?
        ~~~~~~~~~~~~~~~~~
        If you wish to connect XR32 to an ISP via a cable modem, e.g.
        to use it as an Internet Connection Sharing router, you will
        probably need DHCP if your ISP uses dynamic IP addressing.
        However, if your ISP assigns you a static IP address you won't
        need DHCP.

        You will not need DHCP if your connection to the ISP is via
        dial-up PPP, because dynamic IP addresses are assigned as part
        of the PPP negotiation process.

        *** The above scenarios date back to the time when domestic
        routers had not yet become commonplace, when Windows "Internet
        Connection Sharing" was in its unreliable infancy, and XRouter
        was running on DOS machines. Nowadays, with modern ADSL and
        cable routers, and proper TCP/IP built into Windows, it is
        unlikely that XR32 would be required to provide the Internet
        Connection Sharing service.  As a matter of interest however,
        the author is still using DOS XRouter with a cable modem for
        this purpose! ***

        The only reason you might wish to use DHCP these days is to
        obtain a dynamic LAN IP address from your domestic router, but
        this is not recommended practice. It is far better to use
        static IP addresses when feasible, especially when you are
        "port-forwarding" TCP and UDP ports to specific machines.

        You do not need DHCP for normal amateur radio operations.


        Enabling DHCP
        ~~~~~~~~~~~~~
        In XROUTER.CFG, put "DHCP=1" in the appropriate port definition
        block.  There is no need to specify a port IPADDRESS because
        one will be assigned by the DHCP server.  If however, a port
        IPADDRESS is specified (or it is not specified but a global IP
        address is specified), that address will be used for non-DHCP
        traffic until DHCP succeeds in leasing a (possibly different)
        address.  If the global IPADDRESS is 0.0.0.0 or not specified,
        it will be assigned by the first client which obtains a lease.

        To disable DHCP, put "DHCP=0" in the PORT definition block, or
        simply omit the keyword altogether.

        The DHCP command displays DHCP status information, and is
        detailed in DHCP(1).

SEE ALSO
        DHCP(1) -- DHCP Commands.
        XROUTER.CFG(1) -- Main Configuration File.

DHCP(9)                   END OF DOCUMENT