Web-based networking toolkits often offer numerous ways to test routes, domains, and other issues that will directly affect your network.
Network troubleshooting can run the gamut of possibilities. From hardware to software to external, uncontrollable forces, to powerful Jedi mind tricks. When you're troubleshooting networking issues, the problem can often point toward many and varied issues. When that happens, you'll want to have access to tools to help you diagnose the issue. One place to turn for such a tool set is the good old Internet.
Web-based networking toolkits often offer numerous ways to test routes, domains, and other issues that will directly affect your network. I have found five solid web-based tools for you to try out. Some are free, some have a price attached; either way, they are all ready to serve.
1. DNS Stuff
DNS Stuff is one of the more powerful network tool kits around. This particular tool isn't free (though they have a free trial of their Professional Toolkit until August 2013), but it's certainly one of the most comprehensive set of tools you'll find.
Included in the Pro Toolkit are the following: DNS Report (RFC Compliant mitigation steps), ISP Cached DNS Lookup, NS Lookup, Whois//IPWhois Lookup, Top Level Domain Lookup, SSL Examination, Abuse Lookup, Domain Inspector, URL Analyzer, and much more. DNS Stuff also presents you with your external IP address as well as an estimate of your location. With the amount of tools included in the Professional Toolkit, you should be able to troubleshoot numerous external networking issues.
Network-Tools doesn't offer nearly the plethora of tools as does DNS Stuff, but all of their tools are free for the using. Here you will find quick access to: Ping, Trace Route, Whois, Lookup, DNS Records, Blacklist Check, URL Decode/Encode, Email Test, and more.
The Express test will give you the fastest results as it does a combo of Traceroute, DNS, and Whois testing. The report back from that test will often give you the information you need to immediately begin your first steps of troubleshooting the external connection to your route.
3. DNS Inspect
DNS Inspect is the tool you want if you're looking for a fast, free solution that will run fifty tests with a single click. Tests include: IPv6, SOA (Mnam, Rnam, and more), multiple NS tests, multiple MX test, A record tests, glue checks, AAAA records, stealth name servers, hostname, CNAME, mail greeting, accepts postmaster address, WWW tests, and much more. The final report is given a grade and is laid out in such a way that it's easy to spot warnings and failures.
Mr.DNS offers plenty of the standard tools (DNS lookup, DNSSEC lookup, multi-RBL lookup, SMTP test, SPF validation, etc); but it offers one tool that I really think makes it stand out. That tool is the visual traceroute. With this tool you get map of the location of the IP address as well as the route (with clickable addresses that give you information about each hop made between you and the server. The only caveat is that they don't offer a "single click" test that generates a full-blown report for all of the tests.
5. MXToolbox Supertool
MXToolbox Supertool runs a number of tests on your mail server. This test will check DNS, MX records, blacklist, traceroute, SMTP diagnostics, and much more. Once the test is done, there will be clickable links to explain the results as well as what can (or should) be done to reach a resolution. The real power with Supertool comes after you've run the main check on the domain (or IP address). Once the main test is complete, you will be offered a number of links that will run specific tests on the address - that is the meat and potatoes of the MXToolbox Supertool.
There is no such thing as having too many tools at the ready. And when you need to have a web-based test, it's good to have choices. And even if you only come out of this with one or two additional tools for you network administrator's toolkit, you are that much further ahead of the game. You might already have your go-to network admin tool; but having options might be the thing that saves the day.