Ok, lets take it one column at a time:
- Proto is the protocol used. tcp and udp should be pretty self-explanatory. icm is short for ICMP, which is a network control protocol (pings use ICMP echo/reply messages). The number at the end specifies if it's IPv4 or IPv6
- Recv-Q and Send-Q are the receiving and sending queues. If those aren't zero, you're either sending much faster than the other side can read, or you're not reading fast enough yourself.
- Local Address is the local IP and port used, while Foreign Address is the remote site and port.
- State is the state (duh) of the connection. LISTEN means there's a local server listening, ESTABLISHED ...well should be clear, CLOSE_WAIT means you're waiting for confirmation that the connection can be closed. For more details, read up on the TCP protocol.
The second part are UNIX domain sockets, which are a kind of IPC, acting like a network socket.
- The Address is the memory address used
- The queues mean pretty much the same as above
- The Inode is just that. In keeping with "everything is a file", UNIX sockets can be addressed via the respective inode on the filesystem
- Addr is the "address", the "file" used.
For a more in-depth explanation I'd have to read up on it again.