內(nèi)功心法 1.幾種邏輯運(yùn)算 AND OR NOT a AND 0and 0=0 1and1=1 0and1=0 b OR 0OR0=0 1OR1=1 0OR1=1 C NOT NOT0=1 NOT1=0 EXAMPLE: 給一ip地址：139.175.152.254/16 NET ID不用解釋 HOST ID:先將NET MASK 做一個(gè)NOT運(yùn)算，在和IP做一次AND就得出HOST ID Broadcast ID;先將NET MASK作一個(gè)NOT 運(yùn)算，在和IP做一次OR運(yùn)算得出 Broadcast ID 2,招式(一定要將著兩招融會(huì)貫通，包您打遍天下無(wú)敵手) EXAMPLE; a.What are the valid Host ID's for 199.37.2.33/29? Below is avery easy to use shortcut that requires no binary math Figure out the mask :/29=248 Figure out the subnet mask multiple 256-248=8 Subnet are 8 16 24 32 40 48 etc This is subnet32,next subnet is 40.so the broadcast address is 39 Everything between the subnet (32)and broadcast (39) are the valid hosts. In this example .based on the given mask the valid host ranges are 33-38 b.What subnet is the host 200.1.1.130/28 on ? A.200.1.1.128 B.200.1.1.32 C.200.1.1.16 D.200.1.1.64 E.200.1.1.0 Shorhand /28=4 bits in the last octet=decinal 255.255.255.240 Shortcut take 256-240=16 Valid subnets are mutiples of 16 32 48 64......etc Shortcut #2 Because it's a small slice and a big number.who wants to count up every 16 bits to find the next subnetwork address ? Just drivide 130/16=8 bits Now take 8*16 bits = 128.so 130 is on the network 128
