NETMASK

Command

NETMASK -- Display / Set Port NETMASK.

Synopsis

NE[tmask] <port> [value]

Availability

This command is sysop-only.

Description

This command allows the NETMASK for the specified port to be displayed or changed.

The NETMASK is used together with the port IP address to specify the range of IP addresses that are on the same physical network segment as XRPi. If XRPi "overhears" any datagrams with a destination address within that range, and not addressed to itself, it will not attempt to route them.

XRPi and Linux kernal have different IP addresses, but share the same Ethernet address. Thus both XRPi and Linux will "see" the same datagrams. Without a suitable NETMASK value, XRPi would attempt to route any datagram not addressed to itself, which means it would attempt to route any datagrams that are addressed to the Linux kernal IP address.

The netmask is specified in dotted-quad form, for example "255.255.255.0". Any non-zero bit within the netmask specifies that the corresponding bit in the IP address should be non-zero. Any zero bit specifies that the corresponding bit in the IP address may be zero or one. e.g. if the port IP address is "192.168.0.11", and the netmask is "255.255.255.0", XRPi will process datagrams addressed to "192.168.0.11" but will ignore datagrams addressed to any other 192.168.0.x destination (where x represents a number between 0 and 255).

The default value for NETMASK is "0.0.0.0", which disables the function.

The minimum abbreviation for this command is "NE".

Options

If a single numeric argument is supplied, and it is a valid port number, the current NETMASK for that port number is displayed.

If two numeric arguments are supplied, the first specifies a port number and the second specifies a new NETMASK for that port.

Examples

NET 1                 - Display current NETMASK for port 1.
NET 2 255.255.255.0   - Set port 2 NETMASK to "255.255.255.0"

See Also

IPADDRESS(2) -- Display / Set Global or Port IP Address