Git Tutorial

Git is a software source control system, originally developed by Linus Torvalds in 2005 for management of Linux kernel source code across versions. Using Git greatly simplifies the source code management functions for a project and improves the overall efficiency of the software development process.… Read more

iptables

The iptables command is for defining rules for packet filtering in establishing and configuring firewalls in Linux. iptables, also, helps in configuring the Network Address Translation (NAT) for placing a local area network behind a single public IP address for accessing the Internet and for other uses.… Read more

netstat

1. netstat command

The netstat command in Linux provides network statistics and information about the networking subsystem. It gives information about network connections, routing tables and network interface statistics. For example,

$ netstat
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 myhost.local:53744      mail.example.i:imaps    ESTABLISHED
tcp        0      0 myhost.local:36149      example.com:http        ESTABLISHED
tcp        0      0 myhost.local:57051      imap.example.n:imap2    ESTABLISHED
tcp        0      0 myhost.local:51209      mail.example.i:imaps    ESTABLISHED
tcp        0      0 myhost.local:35617      example.com:http        ESTABLISHED
tcp        0      0 myhost.local:51207      mail.example.i:imaps    ESTABLISHED
tcp        0      0 myhost.local:52281      r-198-51-100-12.tw:http ESTABLISHED
tcp        0      0 myhost.local:51208      mail.example.i:imaps    ESTABLISHED
tcp        0      0 myhost.local:52282      r-198-51-100-12.tw:http TIME_WAIT
...
Read more

Routing in Linux

In Internet, the Internet Protocol (IP) is at the Network Layer, which is the third layer of the ISO reference model of network architecture. IP deals with IP packets or datagrams, which are the basic transfer units in the Internet and the higher level protocols like UDP and TCP are built on top of IP datagrams.… Read more

logrotate

Linux daemons write log files. Left to itself, these log files would grow with time and take up the disk space. It is necessary to purge the log files periodically so that the disk space is conserved and is available for smooth running of the system.… Read more