... sev-eral RFCs, including RFCs 24 0 1, 24 0 2, 24 0 6, and 24 0 8. The RFCs describe IP securityextensions for both IPv4 and IPv6. IPSec is built in to the structure of IPv6 protocolsystem. In IPv4, IPv4 is ... 26 -28 protocol system, 22 -23 Application layer, 24 Internet layer, 23 Network Access layer, 23 -24 Transport layer, 23 routing, 121 - 122 direct versus indirect routing, 128 -130distance vector routing,131-133dynamic ... information utilities, 24 8 -25 0connectivity problems, 26 1DNS utilities, 20 0NSLookup, 20 1 -20 3Ping, 20 1nbtstat, 25 9 -26 0netstat, 25 7 -25 8nslookup, 25 3packet sniffers, 26 0 -26 1ping. See pingroute,...