networking-related links i like to have handy:

• ARIN whois
• netsol's whois server
• IANA's TLD listings.
• IANA list of assigned port numbers
• IANA list of assigned protocol numbers
• IANA list of assigned icmp parameters
• yahoo's list of network information centers
• geektools has a whole set of useful tools on their site.
  • traceroute links
  • whois proxy
• traceroute.org
• the rfc editor pages
• the RIPE whois database
• the Routing Arbiter project and pointers to RADB info
• RFC's
• The IETF's Internet Drafts page

• zip4 lookups