Networking Information

Scenario: Your the IT professional in your company and you notice that the previous employee was lazy or unprofessional in updating a network (schematic is a map that links computers, routers, switches, and etc that links up to your network) schematic. Now you need to updated. You notice that on the previous schematic that there are some missing information such as MAC Address, IP Address, or Host Name. Your company policy forbids any users to install any network scanner.


Now your thinking how your going to get all this information well lets explorer our options.


Remember these four tools they will become your friends. these only work in CLI (command line) except for MAC OS X which work in both environment by default. There are tools that do the same thing and this is another way to information that you need without downloading any third-party applications.


In Windows

1. ipconfig "ip address" or "host name"
2. arp -a "ip address"
3. nslookup "ip address"

In Linux / MAC OS X

1. ifconfig "ip address" or "host name"
2. arp -a "ip address"
3. nslookup "ip address"

 In MAC OS X


It has a GUI interface / terminal, but the same as Linux tools.


Depending on how many computers your company has you can go to each computer and look up the computer information. If you don't know how to get computer information for windows, linux, or mac os x. Today I will show how to get this information locally and remotely.


Windows

•  click start > run > type 'cmd'
• At the command prompt type 'ipconfig /all'
•  ipconfig will show you all of the network adapters that connected and disconnected. Also, it show ipaddress, mac address, dns servers, gateway, and etc

Example of the command prompt: 

Ethernet adapter Local Area Connection:

        Connection-specific DNS Suffix  . :
        Description . . . . . . . . . . . : AMD PCNET Family PCI Ethernet Adapter
        Physical Address. . . . . . . . . : 08-00-27-E2-D2-EA
        Dhcp Enabled. . . . . . . . . . . : Yes
        Autoconfiguration Enabled . . . . : Yes
        IP Address. . . . . . . . . . . . : 192.168.1.6
        Subnet Mask . . . . . . . . . . . : 255.255.255.0
        Default Gateway . . . . . . . . . : 192.168.1.1
        DHCP Server . . . . . . . . . . . : 192.168.1.1
        DNS Servers . . . . . . . . . . . : 192.168.1.1
        Lease Obtained. . . . . . . . . . : Wednesday, March 31, 2010 9:35:38 AM

        Lease Expires . . . . . . . . . . : Thursday, April 01, 2010 9:35:38 AM

C:\Documents and Settings\Virtual PC>

This method works for all version Windows. There more ways to find your computer network configuration.


In Linux


depending on what X11 environment you will need to find the terminal. The follow demonstration is based on ubuntu: 

• click on Application > Accessories > Terminal
• at the terminal type 'ifconfig'

Example of the terminal. look at the network interface wlan0:


maddog@DTS-Enterprise:~$ ifconfig
eth0      Link encap:Ethernet  HWaddr 00:23:5a:55:43:b5 
             UP BROADCAST MULTICAST  MTU:1500  Metric:1
             RX packets:0 errors:0 dropped:0 overruns:0 frame:0
             TX packets:0 errors:0 dropped:0 overruns:0 carrier:1
             collisions:0 txqueuelen:1000
             RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
             Interrupt:28

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:4 errors:0 dropped:0 overruns:0 frame:0
           TX packets:4 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:0
           RX bytes:240 (240.0 B)  TX bytes:240 (240.0 B)

wlan0     Link encap:Ethernet  HWaddr 00:24:2b:a2:ed:0f 
              inet addr:192.168.1.5  Bcast:192.168.1.255  Mask:255.255.255.0
              inet6 addr: fe80::224:2bff:fea2:ed0f/64 Scope:Link
             UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
             RX packets:15825 errors:0 dropped:0 overruns:0 frame:0
             TX packets:12572 errors:0 dropped:0 overruns:0 carrier:0
             collisions:0 txqueuelen:1000
             RX bytes:10580654 (10.5 MB)  TX bytes:2682829 (2.6 MB)

maddog@DTS-Enterprise:~$

Hwaddr: is the MAC Address

inet addr: is your IP address

MAC OS X

To find networking information on a Mac running OS X, Click on the Apple logo on the left-hard side and navigate to the Network Preferences panel. Click on "Network" in the System Preferences panel. Under "Show", select the network interface that you want the IP/MAC address for. Generally, this will either be Built-In Ethernet or Airport. To find the IP address, click on the TCP/IP tab. 

On the same screen Under "Show", select the network interface that you want the IP/MAC address for. To find the MAC address of the Ethernet card, click on the Ethernet tab. It will be called "Ethernet ID:"

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Now let say that you know the host name and ip address, but not the MAC address and you do not want to interrupt the employee work. Finding the MAC address in CLI is no problem


In Windows


C:\Documents and Settings\Virtual PC>arp -a 192.168.1.3

Interface: 192.168.1.6 --- 0x10003
  Internet Address      Physical Address      Type
  192.168.1.3           00-22-41-f6-e9-68     dynamic

C:\Documents and Settings\Virtual PC>


In Linux


maddog@DTS-Enterprise:~$ arp -a 192.168.1.3
Macintosh-110.local (192.168.1.3) at 00:22:41:f6:e9:68 [ether] on wlan0
maddog@DTS-Enterprise:~$


In MAC OS X

You'll find the Terminal in the Utilities folder within the Applications folder. It is the same command as in linux 

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Now let say that you know the MAC Address and ip address, but not the Host Name and you do not want to interrupt the employee work. Finding the Hostname in CLI is no problem. This will require a DNS server in order to work properly.

In Windows 

C:\Documents and Settings\Virtual PC>nslookup 127.0.0.1
*** Can't find server name for address 192.168.1.1: Non-existent domain
*** Default servers are not available
Server:  UnKnown
Address:  192.168.1.1

Name:    localhost  < Normally this will display the computer name.
Address:  127.0.0.1


C:\Documents and Settings\Virtual PC>

In Linux

maddog@DTS-Enterprise:~$ nslookup 127.0.0.1

Server:        192.168.1.1

Address:    192.168.1.1#53

Non-authoritative answer:

1.0.0.127.in-addr.arpa    name = localhost. < Normally this will display the computer name.

Authoritative answers can be found from:

maddog@DTS-Enterprise:~$

In MAC OS X

• Launch the Network Utility.
• In the Network Utility window, click the Lookup tab.
• In the field under "Please enter an internet address to lookup", enter the IP address or domain name of the computer you are looking up.
• In the pop-up menu next to "Select the information to lookup:", select Default Information.
• Uncheck the checkbox next to Use "dig" in place of "nslookup".
• Click the Lookup button.
• This will show the IP address of the domain you entered and will also show what name-servers you are using to get the IP address.

That's all now next week I will show you how to recover deleted files on any operating system.

Want to read this off-line you can download it at my other site http://dtsenterprise.tech.officelive.com and click on Documentations. You will see more examples that I could not display and there are screen shoots for better a visual.

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