address mask
  • A bit combination which identifies which portion of an IP address corresponds to the network or subnetwork, and blocks out the rest. For example, a network may use the same values in the first three address fields of a four field address such as WWW.XXX.YYY.ZZZ, and block out, or mask, all but the ZZZ portion, since it is the only one that will vary. Also called subnetwork mask.

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