netmask

netmask

(networking)
A 32-bit bit mask which shows how an Internet address is to be divided into network, subnet and host parts. The netmask has ones in the bit positions in the 32-bit address which are to be used for the network and subnet parts, and zeros for the host part. The mask should contain at least the standard network portion (as determined by the address's class), and the subnet field should be contiguous with the network portion.

If a `+' (plus sign) is given for the netmask value, then the network number is looked up in the NIS netmasks.byaddr map (or in the /etc/netmasks) file if not running the NIS service.

Unix manual page: ifconfig(8).
References in periodicals archive ?
Every route is added to the firewall by hand and the smallest netmask possible is used so traffic will not reach unintended devices if the firewall has no policy.
Administrators can check IP address on netmask, gateway/routers and domain servers, and access DHCP hosts to obtain network information.
While previous versions of the Barracuda Spyware Firewall included custom blocking rules for arbitrary URLs and MIME file types, the Barracuda Spyware Firewall now allows administrators to define custom application-blocking policies by source or destination IP address, netmask, and port number.
Improved netmask management provides quick access to connection streams.