Q. How do I find out subnet mask on UNIX operating system? Can you tell us the name of command and configuration file to store subnetmask under UNIX?
A. A subnetwork/ subnet is a range of logical addresses within the address space that is assigned to an organization. Subnetting is a hierarchical partitioning of the network address space of an organization (and of the network nodes of an autonomous system) into several subnets. Routers constitute borders between subnets. Communication to and from a subnet is mediated by one specific port of one specific router, at least momentarily.
Under UNIX / Linux, you need to use the ifconfig utility to assign an address to a network interface
and/or configure network interface parameters. Same command can display subnet. Just type command ifconfig:
$ /sbin/ifconfig interface-name
mtu 1500 inet 18.104.22.168 netmask 0xfffffff8 broadcast 22.214.171.124 ether 00:0c:29:32:8a:8c plip0: flags=108810 mtu 1500 lo0: flags=8049 mtu 16384 inet6 fe80::1%lo0 prefixlen 64 scopeid 0x3 inet6 ::1 prefixlen 128 inet 127.0.0.1 netmask 0xff000000
Look for inet line you will see an IP address, followed by netmask.