favorite network troubleshooting tools (online)

[Mehmet Akcin <mehmet () akcin net>]

hey there,

I recently have come across this http://ping.pe/ website, I have no
association with this but it's pretty awesome. This made me wonder what
other tools out there which I do not know about it.

what are your favorite network troubleshooting tools?

In addition to ping.pe, I like https://bgp.he.net but would love to hear
your thought about other tool recommendations as especially the ones that
are distributed.

Mehmet