Basic concepts • Host name: machine.sub-domain.domain • example: mail.ubalt.edu • same machine name in Windows in NetBIOS and TCP/IP, but the NetBIOS name is just \\machine • IP numbers are assigned to NICs • a machine can have more than one NIC • one NIC can have more than one IP number • use IPCONFIG to see IP numbers in a machine • example in AL 200 and WEBTEACH • How to map host names to IP numbers? • Host tables, DNS and WINS
IP resolution • Name resolution: given a TCP/IP name how to know its corresponding IP number. • Alternatives • HOSTS file: an ASCII list of host names and IP numbers, • IP broadcast: workstation asks for IP number (resolution) • LMHOSTS file: does all HOSTS do plus include part of the table from central location, identify DC, Domain, etc. Both at \%system root%\Windows\System32\Drivers\etc • DNS: a data base containing zone, cache, reverse lookup, and arpa-127 files (resource records), located at \%system root%\Windows\System32\Dns directory, DHCP updates DNS in Windows 2000 on (not in NT). • WINS: uses a replicated data base with computer names and IP numbers, dynamic, interacting with DHCP.
IP routing • Routing tables • Static - maintained by network manager (NT) • Dynamic - automatically by routing protocol • DNS • required for socket applications (FTP, HTTPD, MAIL) • DNS service, dynamic link to WINS but requires manual updating of central route table , RIP takes care of the rest (NT). DHCP automatically updates DNS in Windows 2K on • DNS data base: boot (where are the files), arpa-127.rev (maps localhost into 127.0.0.1), cache (where the “root servers” are located in the Internet), direct and reverse lookup table of names and IP numbers . • Primary and secondary name servers: one of each by zone.
IP routing tools • Nslookup • information, e.g. nslookup <webteach> • commands: set option , e.g. domain, port(53). • Viewing the route table • netstat -rn or route print • example in AL 200 and WEBTEACH • note: 0.0.0.0 is Internet connection • Trace route • tracert: example in AL200 and WEBTEACH • Cyberkit: example in AL200