Useful Tools
- ADSL in the UK: How it works
- Network packet tracing and protocol analysis (freeware): WireShark
- Ping routing/response timing (freeware and shareware versions): PingPlotter
- Online subnet calculator
- Display your own external IP Address: What’s my IP?
- DNS Lookup (online): Domain Dossier or IPTools
- TCP/UDP Port List
- Windows Networking: Command Line Tools
- Public NTP Time servers
