Usefull Linux networking commands

• /etc/rc.d/init.d/network start - command to start, restart or stop the network
• netstat - Display connections, routing tables, stats etc
* List externally connected processes: netstat -punta
* List all connected processes: netstat -nap
* Show network statistics: netstat -s
* Kernel interface table info: netstat -a -i eth0
• ping - send ICMP ECHO_REQUEST packets to network hosts. Use Cntl-C to stop ping.
• traceroute - print the route packets take to network host.
(Ubuntu Note: Typically Ubuntu installs tracepath for IPv4 and traceroute6 for IPv6. One can install traceroute: apt-get install traceroute)
* traceroute IP-address-of-server
* traceroute domain-name-of-server
• mtr - a network diagnostic tool introduced in Fedora - Like traceroute except it gives more network quality and network diagnostic info. Leave running to get real time stats. Reports best and worst round trip times in milliseconds.
* mtr IP-address-of-server
* mtr domain-name-of-server
• whois - Lookup a domain name in the internic whois database.
• finger - Display information on a system user. i.e. finger user@host Uses $HOME/.plan and $HOME/.project user files. Often used by game developers. See http://finger.planetquake.com/
• iptables - IP firewall administration (Linux kernel 2.6/2.4) See YoLinux firewall/gateway configuration.
• ipchains - IP firewall administration (Linux kernel 2.2) See YoLinux firewall/gateway configuration.
• socklist - Display list of open sockets, type, port, process id and the name of the process. Kill with fuser or kill.
• host - Give a host name and the command will return IP address. Unlike nslookup, the host command will use both /etc/hosts as well as DNS.
Example: host domain-name-of-server
• nslookup - Give a host name and the command will return IP address. Also see Testing your DNS (YoLinux Tutorial) Note that nslookup does not use the /etc/hosts file.

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