Name Resolution Protocols

NetBIOS

• Pre DNS
• Microsoft protocol
• Used Broadcasting (unwieldy on large networks)
• Designed for un-routed networks with fewer than 40 hosts

NetBIOS over TCP/IP (NetBT)

• remove reliance on NetBEUI
• Ports (yes, these are correct…):
  • tcp:137 name registration and resolution
  • tcp:139 connection-oriented communication
  • udp:137 name registration and resolution
  • udp:138 datagram distribution service
• NetBT is used only on the LAN. So a host has one NetBT name on the LAN, and can have a different one on the WAN (which uses DNS)

Domain Name Services DNS

DNS Names

• DNS Names can be made of a-z, 0-9, and -
• Capitalization does not matter
• Can be up to 255 characters long, including separating .s

Root Servers

There are 13 servers that sit at the top of the Domain Server stack. These delegate responsibilities to their top level domain servers.

Top Level Domain Servers

These handle the Top Level Domain Names. E.g. .com, .net, .gov, etc.

Second Level Servers

These support individual computers.