These free links have made themselves very useful to us in the past, we hope they become of use to you too:

• DNSstuff/DNSreport: All sorts of debugging tools for DNS and other services.

• ARIN: American Registry for Internet Numbers.

• traceroute.org: Hundreds of tracerouting servers.

• FixedOrbit: Map of the internet and network exploration site.

• CIDR-report: IPv4, IPv6, BGP and AS Path reports.

• RobTex: Multi-RBL check and AS-numbercheck.

• RADb: Routing Address Database.

• AltDB: Alternative Routing Registry Project.

• InternetPulse: Internet Carrier Health Report.