Network Debugging

This article or section is a candidate for merging with Network Configuration.

Notes: already duplicates part of its content (Discuss in Talk:Network Debugging)

Ping & Tracepath/Traceroute

See Network_configuration#Check_the_connection.

Tcpdump

tcpdump, and its underlying library libpcap, are multi-platform user space interfaces to the packets on the network. It should be emphasized they do see, they can capture, any inbound packets that reach the local NIC. No matter if the local software firewall is blocking those packets, or not. On the other hand, they can only see outbound packets the firewall passes through: [1]

A short, unintimidating introduction to tcpdump, with examples, is at: [2]