Index Note to the Reader: Throughout this index boldfaced page numbers indicate primary discussions of a topic. Italicized page numbers indicate illustrations. A A (address) records, 47 A A A (authentication, authorization, and accounting), 190 AAAA records, 48 access control lists (ACL s) firewalls, 204 over view, 180 ­182 access securit y, 180 ACL s, 180 ­182 remote access, 184 ­188 , 185 ­186 tunneling and encr yption, 182 ­184 accounting in A A A , 190 ACL s (access control lists) firewalls, 204 over view, 180 ­182 active at tacks, 197 active hubs, 13 address (A) records, 47 Address Resolution Protocol (A R P) arp ser vice, 152 ­154, 153 description, 39 over view, 43 ­ 44 addresses I P. See I P addresses M AC , 10 with arp, 154 filters, 64, 179 ­181 format, 21­22 , 22 A DSL (asym metric digital subscriber line), 112 agents in SN M P, 46, 159 A irMagnet tool, 76 A merican Registr y for I nternet Numbers (ARIN), 17 antennas, 67 anycast addressing, 26 A PI PA (Automatic Private I nternet Protocol Addressing) addresses, 26 ­27 A PN IC (Asia Pacific Net work I nformation Centre), 17 Application layer OSI model, 8 TC P/ I P model, 9 A R I N (A merican Registr y for I nternet Numbers), 17 A R P (Address Resolution Protocol) arp ser vice, 152 ­154, 153 description, 39 over view, 43 ­ 44 Asia Pacific Net work I nformation Centre (A PN IC), 17 asset management, 164 asym metric digital subscriber line (A DSL), 112 asynchronous transfer mode (ATM), 116 at tack t ypes, 197­200 at tenuation in cable, 125­126 authentication, authorization, and accounting (A A A), 190 authentication, user, 188 ­194 authenticators in 802 .1x, 191 authorization in A A A , 190 Automatic Private I nternet Protocol Addressing (A PI PA) addresses, 26 ­27 autonomous systems, 33 availability, 166 awareness for threat mitigation, 200 B B (bearer) channels, 111 bands in wireless net works, 107