186 Index H Data link layer, 74­75 functions of, 157 sublayers of, 75 troubleshooting, 165­166 Data translation, 77 Data transmission full duplex, 25 half-duplex, 25 simplex, 25 D connectors, 30 Decentralized network topology, 4 Decimal to binary conversion, 91 Default gateways, 50 Default subnet mask, 94 Demarc, 27 Demilitiarized zone (DMZ) layered implementation, 49 multiple interface firewall implementation, 49 Denial of service (DoS), 131 Department of defense (DoD) model, Dynamic host configuration protocol (DHCP), 50, 84, 96, 97 Dynamic routing, classifications, 101 E E-mail relaying server, 126 Eavesdropping, 22 Electromagnetic (EM) field, 57 Electromagnetic interference (EMI), 21 Encapsulation, 73 Enhanced interior gateway routing protocol (EIGRP), 102 Ethernet, 28 types of, 28 NIC, 81 Extensible authentication protocol (EAP), 138 Extensible authentication protocol over LAN (EAPoL), 65 Extensible authentication protocol over wireless (EAPoW), 65 Hardware loopback adapter, 24 High availability protocol, 149 Honeynets, characteristics of, 124 Honeypot, characteristics of, 123­124 Host-to-host layer, 82 Host address space, 91 Host ID, 91, 92 classes, 93 rules for, 93 Hub-and-spoke topology, 11 Hubs, 37 active, 38 characteristics of, 37 passive, 38 troubleshooting, 165 Hybrid topology, 11 Hypertext transfer protocol (HTTP), 85, 125, 169