Kali Linux Network Commands are tools for Configuring

Computers are connected in association extremely network to exchange knowledge or resources each other. a pair of or a great deal of portable computer connected through network media cited as the network. There are vary of network devices or media ar involved to create the network. portable computer loaded with UNIX operating system OS will even be a district of network whether or not or not it's a little or large network by its multitasking and multiuser natures. Maintaining of system and network up and running can be a task of the System / Network Administrator’s job. throughout this text, we tend to ar planning to review often used network configuration and troubleshoot commands in UNIX operating system. 

1. iFconfig

ifconfig (interface configurator) command is used to initialize an interface, assign IP Address to interface and enable or disable interface on demand. With this command, you can view IP Address and Hardware / MAC address assign to interface and also MTU (Maximum transmission unit) size.

# ifconfig

eth0 Link encap:Ethernet HWaddr 00:0C:29:28:FD:4C
inet addr:192.168.50.2 Bcast:192.168.50.255 Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fe28:fd4c/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:6093 errors:0 dropped:0 overruns:0 frame:0
TX packets:4824 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:6125302 (5.8 MiB) TX bytes:536966 (524.3 KiB)
Interrupt:18 Base address:0x2000
or
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:8 errors:0 dropped:0 overruns:0 frame:0
TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:480 (480.0 b) TX bytes:480 (480.0 b)

ifconfig with interface (eth0) command only shows specific interface details like IP Address, MAC Address etc. with -a options will display all available interface details if it is disable also.

# ifconfig eth0

eth0      Link encap:Ethernet  HWaddr 00:0C:29:28:FD:4C
          inet addr:192.168.50.2  Bcast:192.168.50.255  Mask:255.255.255.0
          inet6 addr: fe80::20c:29ff:fe28:fd4c/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:6119 errors:0 dropped:0 overruns:0 frame:0
          TX packets:4841 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:6127464 (5.8 MiB)  TX bytes:539648 (527.0 KiB)
          Interrupt:18 Base address:0x2000 

Assigning IP Address and Gateway Assigning an IP Address and Gateway to interface on the fly. The setting will be removed in case of system reboot.

# ifconfig eth0 192.168.50.5 netmask 255.255.255.0 

Enable or Disable Specific Interface To enable or disable specific Interface, we use example command as follows. Enable eth0

# ifup eth0

Disable eth0

# ifdown eth0 

Setting MTU Size By default MTU size is 1500. We can set required MTU size with below command. Replace XXXX with size.

# ifconfig eth0 mtu XXXX

Set Interface in Promiscuous mode Network interface only received packets belongs to that particular NIC. If you put interface in promiscuous mode it will received all the packets. This is very useful to capture packets and analyze later. For this you may require superuser access.

# ifconfig eth0 - promisc

2. PING Command 

PING (Packet INternet Groper) command is the best way to test connectivity between two nodes. Whether it is Local Area Network (LAN) or Wide Area Network (WAN). Ping use ICMP (Internet Control Message Protocol) to communicate to other devices. You can ping host name of ip address using below command.

# ping 4.2.2.2
PING 4.2.2.2 (4.2.2.2) 56(84) bytes of data.
64 bytes from 4.2.2.2: icmp_seq=1 ttl=44 time=203 ms
64 bytes from 4.2.2.2: icmp_seq=2 ttl=44 time=201 ms
64 bytes from 4.2.2.2: icmp_seq=3 ttl=44 time=201 mscode 
OR
# ping www.hackinglearn.com
PING hackinglearn.com (50.116.66.136) 56(84) bytes of data.
64 bytes from 50.116.66.136: icmp_seq=1 ttl=47 time=284 ms
64 bytes from 50.116.66.136: icmp_seq=2 ttl=47 time=287 ms
64 bytes from 50.116.66.136: icmp_seq=3 ttl=47 time=285 ms

In Linux ping command keep executing until you interrupt. Ping with -c option exit after N number of request (success or error respond)

# ping -c 5 www.hackinglearn.com
PING hackinglearn.com (50.116.66.136) 56(84) bytes of data.
64 bytes from 50.116.66.136: icmp_seq=1 ttl=47 time=285 ms
64 bytes from 50.116.66.136: icmp_seq=2 ttl=47 time=285 ms
64 bytes from 50.116.66.136: icmp_seq=3 ttl=47 time=285 ms
64 bytes from 50.116.66.136: icmp_seq=4 ttl=47 time=285 ms
64 bytes from 50.116.66.136: icmp_seq=5 ttl=47 time=285 ms

--- hackinglearn.com ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4295ms
rtt min/avg/max/mdev = 285.062/285.324/285.406/0.599 ms