This is a list of tools to check server connectivity and path issues that I found useful recently:

• Just-Ping: allows you to ping a server from several locations around the world, 34 when writing this.
• Just-Traceroute: allows you to do a traceroute from 4 locations around the world.
• HTTPTracer: an application that sits between your HTTP client and your HTTP server and sniffs all the communication that goes on between the two. Allows you to check data encoding, HTTP headers, if caching system works, etc.
• mon.itor.us: check if your websites are online and warn you if they fail
• Are my sites up?: check if your websites are online and warn you if they fail

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