netmasks(4tcp)

netmasks -- network mask data base

Synopsis

/etc/netmasks

Description

The netmasks file contains network masks used to implement IP standard subnetting.

Files

/var/yp/domainname/netmasks.byaddr: Corresponding NIS map containing network masks to be used with IP subnetting. The mask is the key in the map.

Usage

For each network that is subnetted, a single line should exist in this file with the network number, any number of <Space> or <Tab> characters, and the network mask to use on that network. Network numbers and masks may be specified in the conventional IP ``.'' notation (like IP host addresses, but with zeroes for the host part).

When the Network Information Service (NIS) is in use, it references the NIS map netmasks.byaddr on the NIS server instead of /etc/netmasks.

References

ifconfig(1Mtcp)

Examples

   128.32.0.0 255.255.255.0

can be used to specify that the Class B network 128.32.0.0 should have eight bits of subnet field and eight bits of host field, in addition to the standard sixteen bits in the network field.