1. Linux Ubuntu 12.04
Network Commands 3
A.S

2. Network Configuration
nslookup, which stands for "name server lookup", is a useful tool for finding out information about a named domain. By default, nslookup will translate a domain name to an IP address (or vice versa)

3. Network Configuration
NSLOOKUP Command
nslookup command also use to find out DNS related query. The following examples shows A Record (IP Address) of tecmint.com.
nslookup uobabylon.edu.iq
nslookup is a command-line administrative tool for testing and troubleshooting DNS servers (Domain Name Server). It is used to query specific DNS resource records (RR) as well. Most operating systems comes with built-in nslookup feature.

4. Network Configuration

5. Network Configuration

6. Network Configuration
Querying The NS Record Of A Domain
The NS Record of a domain is a map of all name servers that are authoritative for that domain. You can query a domain's NS Record using the option -type=ns, like this:
nslookup -type=ns microsoft.com

7. Network Configuration

8. Network Configuration

9. Network Configuration
Querying The MX Record
The MX Record is a map of mail exchange servers for a domain. When you send to a domain, for example mail is routed to Microsoft's MX servers. You can query a domain for its MX Record using the -type=mx option. For example:
nslookup -type=mx microsoft.com

10. Network Configuration

11. Network Configuration
ARP Command
ARP (Address Resolution Protocol) is useful to view / add the contents of the kernel’s ARP tables. To see default table use the command as.
arp -e
ARP stands for Address Resolution Protocol, which is used to find the media access control address of a network neighbour for a given IPv4
Address.

12. Network Configuration
Arp-scan
Arp-scan is a commandline utility for linux that can be used to scan the network of a certain interface for alive hosts. It shows
the ip address and mac addresses of all the hosts/nodes found.
sudo apt-get install arp-scan
In place of the localnet option arp-scan can also take a range of ip addresses to scan. For example :
$ sudo arp-scan --interface=eth /24

13. Network Configuration
IWCONFIG Command
iwconfig command in Linux is use to configure a wireless network interface. You can see and set the basic Wi-Fi details like SSID channel and encryption. You can refer man page of iwconfig to know more.
iwconfig [interface]

14. Network Configuration
telnet
Connects destination host via telnet protocol, if telnet connection establish on any port means connectivity between two hosts is working fine. telnet hostname port   will telnet hostname with the port specified. Normally it is used to see whether host is alive and network connection is fine or not.
telnet server_name
telnet
telnet