When traceroute lies
Asterisks are not failures and high latency at hop four is usually nothing. Read it correctly.
Writing
icmp
TTL as a diagnostic instrument
The time-to-live field quietly tells you how many hops a packet took. That is more useful than it sounds.
Why ping succeeds and the application still fails
A successful ping proves less than people think. Here is exactly what it proves, and what it does not.