With the recent problems on the internet yesterday due to BGP hitting 512k Routes , heres an example to diagnose BGP problems!

Nslookup on pariswells.com gives us the IP 108.162.200.103

AAPT have a looking glass here http://looking-glass.connect.com.au/lg

gives the results below

The second path in red is used. The AS numbers go from source to destination so we went from

1221 (Telstra Australia) -> 10026 (pacnet Hong Kong) -> 13335 (Cloudflare US)

If we didn’t see any route or a route to the wrong AS number we could see a problem. It’s also a good idea to check with another looking glass (this one is in Canada)

 852 (telus Canada) -> 13335 (Cloudflare US) -> 13335 -> 13335