IPConfig – All you need to know

All About IPCONFIG

ipconfig (Internet Protocol Configuration) in Microsoft Windows is a console application that displays all current TCP/IP network configuration values and refreshes Dynamic Host Configuration Protocol DHCP and Domain Name System DNS settings. Similar GUI tools named winipcfg (Win98 / WinMe)  also exists.

ipconfig in Mac OS X serves as a wrapper to the IPConfiguration agent, and can be used to control the BootP and DHCP client from the command line interface. Like most UNIX-based operating systems, Mac OS X also uses ifconfig for more direct control over network interfaces, such as configuring static IP addresses.

In Unix and Unix-like operating systems, the ifconfig command is used instead of ipconfig.

The ipconfig.exe command is an external command and is available in following Microsoft operating systems

• Windows 95
• Windows 98
• Windows ME
• Windows 2000
• Windows XP
• Windows Vista

What is ipconfig
Ipconfig is a DOS utility which can be used from MS-DOS and a MS-DOS shell to display the network settings currently assigned and given by a network. This command can be utilized to verify a network connection as well as to verify your network settings

Examples
Below is an example of the output you should expect to see when running ipconfig /all Because of security concerns, the below network information is false.

Windows XP IP Configuration

Host Name . . . . . . . . . : COMPUTERName1
DNS Servers . . . . . . . . : 123.45.67.8
111.111.111.1
111.111.111.1
Node Type . . . . . . . . . : Broadcast
NetBIOS Scope ID. . . . . . :
IP Routing Enabled. . . . . : No
WINS Proxy Enabled. . . . . : No
NetBIOS Resolution Uses DNS : No

0 Ethernet adapter :

Description . . . . . . . . : PPP Adapter.
Physical Address. . . . . . : 22-33-44-55-00-00
DHCP Enabled. . . . . . . . : Yes
IP Address. . . . . . . . . : 123.45.67.802
Subnet Mask . . . . . . . . : 255.255.0.0
Default Gateway . . . . . . : 123.45.67.801
DHCP Server . . . . . . . . : 255.255.255.255
Primary WINS Server . . . . :
Secondary WINS Server . . . :
Lease Obtained. . . . . . . : 11 11 08 12:00:00 AM
Lease Expires . . . . . . . : 11 11 08 12:00:00 AM

1 Ethernet adapter :

Description . . . . . . . . : 3Com 3C90x Ethernet Adapter
Physical Address. . . . . . : 20-50-44-62-F7-23
DHCP Enabled. . . . . . . . : Yes
IP Address. . . . . . . . . : 111.111.111.104
Subnet Mask . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . : 111.111.111.1
DHCP Server . . . . . . . . : 111.111.111.1
Primary WINS Server . . . . :
Secondary WINS Server . . . :
Lease Obtained. . . . . . . : 11 12 00 10:10:34 PM
Lease Expires . . . . . . . :

Other Commands
ipconfig /displaydns
Running the above command would display all the DNS information.

ipconfig /flushdns
Delete all DNS entries.

ipconfig help
If you would like to see what all switches you can give to ipconfig – refer to the output below (or get it on your own computer by Start -> Run -> CMD -> Type ipconfig /? to get Help on ipconfig command)

C:\>ipconfig /?

USAGE:
ipconfig [/? | /all | /renew [adapter] | /release [adapter] | /flushdns | /displaydns | /registerdns | /showclassid adapter |  /setclassid adapter [classid] ]

where
adapter   Connection name
(wildcard characters * and ? allowed, see examples)

Options:
/? Display this help message
/all Display full configuration information.
/release Release the IP address for the specified adapter.
/renew Renew the IP address for the specified adapter.
/flushdns Purges the DNS Resolver cache.
/registerdns Refreshes all DHCP leases and re-registers DNS names
/displaydns Display the contents of the DNS Resolver Cache.
/showclassid Displays all the dhcp class IDs allowed for adapter.
/setclassid Modifies the dhcp class id.

The default is to display only the IP address, subnet mask and default gateway for each adapter bound to TCP/IP.

For Release and Renew, if no adapter name is specified, then the IP address leases for all adapters bound to TCP/IP will be released or renewed.

For Setclassid, if no ClassId is specified, then the ClassId is removed.

Examples:
> ipconfig                   … Show information.
> ipconfig /all              … Show detailed information
> ipconfig /renew            … renew all adapters
> ipconfig /renew EL*        … renew any connection that has its
name starting with EL
> ipconfig /release *Con*    … release all matching connections,
eg. “Local Area Connection 1″ or
“Local Area Connection 2″