DNSstuff is an all-in-one suite of network and administration applications used to diagnose, monitor, and secure networks. The suite of tools includes DNS audit and lookup tools, an IP address locator, a traceroute tool, a network bandwidth monitor, a threat assessment tool, a WHOIS lookup, a domain name system management tool, and an IP address calculator. The suite also includes an SSL/TLS checker, a blacklist checker, an email testing tool, a real-time DNS lookup tool, a directory lookup tool, and a domain name system monitoring tool. DNSstuff also provides 24/7 network monitoring and reporting, as well as a host of other features designed to help users maintain and secure their networks.
Almost exactly the same tools, and just like the original design of dnsstuff in the mid 2000's, totally free without having to pay to access all their tools.
Discontinued Appears to be discontinued. The server reports an error.
Pingdom is for uptime monitoring, not for server debugging/troubleshooting tools.