Recipe: Basic networking primer

ifconfig example:
=================

$ ifconfig
lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0 
          inet6 addr: ::1/128 Scope:Host 
          UP LOOPBACK RUNNING  MTU:16436  Metric:1 
          RX packets:6078 errors:0 dropped:0 overruns:0 frame:0 
          TX packets:6078 errors:0 dropped:0 overruns:0 carrier:0 
          collisions:0 txqueuelen:0 
          RX bytes:634520 (634.5 KB)  TX bytes:634520 (634.5 KB) 

wlan0     Link encap:Ethernet  HWaddr 00:1c:bf:87:25:d2  
          inet addr:192.168.0.82  Bcast:192.168.3.255  Mask:255.255.252.0 
          inet6 addr: fe80::21c:bfff:fe87:25d2/64 Scope:Link 
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1 
          RX packets:420917 errors:0 dropped:0 overruns:0 frame:0 
          TX packets:86820 errors:0 dropped:0 overruns:0 carrier:0 
          collisions:0 txqueuelen:1000 
          RX bytes:98027420 (98.0 MB)  TX bytes:22602672 (22.6 MB) 


Printing list of network interfaces
===================================
$ ifconfig | cut -c-10 | tr -d ' ' | tr -s '\n'
lo
wlan0

Set IP address for a network interface
======================================
# ifconfig wlan0 192.168.0.80 

Set subnet mask along with IP address
======================================
# ifconfig wlan0 192.168.0.80  netmask 255.255.252.0

Spoofing Hardware Address (MAC Address)
=======================================

# ifconfig eth0 hw ether 00:1c:bf:87:25:d5


00:1c:bf:87:25:d5 is the new Hw Address to be assigned and eth0 is the interface


DNS lookup
==========

$ host google.com 
google.com has address 64.233.181.105 
google.com has address 64.233.181.99 
google.com has address 64.233.181.147 
google.com has address 64.233.181.106 
google.com has address 64.233.181.103 
google.com has address 64.233.181.104 

$ nslookup google.com 
Server:		8.8.8.8 
Address:	8.8.8.8#53 

Non-authoritative answer: 
Name:	google.com 
Address: 64.233.181.105 
Name:	google.com 
Address: 64.233.181.99 
Name:	google.com 
Address: 64.233.181.147 
Name:	google.com 
Address: 64.233.181.106 
Name:	google.com 
Address: 64.233.181.103 
Name:	google.com 
Address: 64.233.181.104 

Server:		8.8.8.8 


route
=====

$ route 
Kernel IP routing table 
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface 
192.168.0.0     *               255.255.252.0   U     2      0        0 wlan0 
link-local      *               255.255.0.0     U     1000   0        0 wlan0 
default         proxy-4.local   0.0.0.0         UG    0      0        0 wlan0 


$ route -n 
Kernel IP routing table 
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface 
192.168.0.0     0.0.0.0         255.255.252.0   U     2      0        0 wlan0 
169.254.0.0     0.0.0.0         255.255.0.0     U     1000   0        0 wlan0 
0.0.0.0         192.168.0.4     0.0.0.0         UG    0      0        0 wlan0 

Adding route
============
# route add default gw 192.168.0.1 wlan0