My Favorite Network Testing and Diagnostic Tools:
| Online Tools | URL | Description |
| IPv4 Subnet Calculator | https://jodies.de/ipcalc | IPv4 address and netmask and calculator |
| IPv6 Subnet Calculator | http://www.gestioip.net/cgi-bin/subnet_calculator.cgi | Powerful free online IPv4/IPv6 subnet calculator, hierarchical addressing planner and IP address converter |
| Test IPv6 | https://test-ipv6.com | Test your browser and connection for IPv6 readiness |
| BGP Route Servers | https://www.routeservers.org | Most updated BGP Route Servers List in Internet |
| HE BGP Toolkit | https://bgp.he.net | Hurricane Electric BGP Toolkit |
| HE Looking Glass | https://lg.he.net | Hurricane Electric’s Network Looking Glass. |
| Urih | https://urih.com | Free online network tools & utilities (smart whois,hash & CRC,benchmarker,reverse IP,subnet calc, etc) |
| Tcpdump 101 | https://tcpdump101.com | Build packet capture syntax for a variety of network devices |
| MXToolBox | https://mxtoolbox.com | Free Blacklist, DNS and Email tools |
| Central Ops | https://centralops.net/co/ | Free online network tools (ping, traceroute,nslookup) based on Dallas,Texas.,USA. Can use for free for 50 times per day |
| IP Geo Location | https://ipgeolocation.io | Free IP Geolocation API and Accurate IP Lookup Database (including latitude & longitude) |
| DSL Reports | https://www.dslreports.com/tools | Speed tests, ping tests and bandwidth tools |
| PeeringDB | https://www.peeringdb.com | Freely available, user-maintained, database of networks, and the go-to location for interconnection data. |
| Down Detector | https://downdetector.com | Real-time problem & outage monitoring |
| WebPage Test | https://www.webpagetest.org | Web page Performance Testing Tool |