From the above network IP address the mask will be 2552552400. In order to do this you must first find your Skype contacts username. Subnet Mask Table A class A network number uses the first eight bits of the IP address as its network part The remaining 24 bits comprise the host part of the IP address as illustrated in Figure 3-2 below. . Figure 3-2 Byte Assignment in a Class A Address. Class B network address has 16 bits available for host addressing 14 bits for subnetting 2 bits for host addressing. This is sometimes known as the dot address and more technically as dotted quad notationFor Class A IP addresses the numbers would represent networklocallocallocal. Network IDs 2¹⁴ 16384 network ID. Given network address1721600 20. The subnet mask for class B is 25525500. These classes are class A class B and class C. The IP address is usually expressed as four decimal numbers each representing eight bits sepa