IPCONFIG – Part 1 – The Basics

What is IPCONFIG?

IPCONFIG is a very common command line that any Windows administrators have to know how to use it. The most common feature of IPCONFIG is to show the current IP configuration of a computer. There are some advanced features of IPCONFIG command that could help network administrators to resolve their network problems. These features include, but not limited to, displaying IP configuration, displaying MAC address, releasing current IP, requesting a new IP, registering current IP and hostname to DNS Server. Moreover, some super advanced features, such as setclassID and showclassID could categorize DHCP Clients into groups with special options.

Here are some demonstrations of how to use IPCONFIG command

IPCONFIG examples

Displaying IP configuration of local host

IPCONFIG

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :
Link-local IPv6 Address . . . . . : fe80::111a:12e5:5473:4f64%11
IPv4 Address. . . . . . . . . . . : 192.168.11.1
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.11.254

 

Displaying IP and Mac Address configuration of local host

IPCONFIG /ALL

Windows IP Configuration

Host Name . . . . . . . . . . . . : HaoNguyen-PC
Primary Dns Suffix . . . . . . . : plaintuts.com
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : plaintuts.com

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Intel(R) 82579LM Gigabit Network Connection
Physical Address. . . . . . . . . : 18-03-73-AC-4D-03
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::111a:12e5:5473:4f64%11(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.11.1(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.11.254
DHCPv6 IAID . . . . . . . . . . . : 236454771
DHCPv6 Client DUID. . . . . . . . : 00-01-00-01-15-C4-20-54-18-03-73-AD-BD-13
DNS Servers . . . . . . . . . . . : 192.168.11.3
NetBIOS over Tcpip. . . . . . . . : Enabled

It sounds like a boring command, isn’t it? Keep going, here are some useful functions of IPCONFIG command.

Release current IP configuration. This command is applied to DHCP Clients only.

IPCONFIG /Release

The command IPCONFIG /Release will release all IP configurations on all local interfaces. If you prefer to release certain interfaces, this command should help too. To release IP on selection of interfaces, issue this command

Release IP on specific interface

IPCONFIG /Release “*Local*”

“*Local*” is the pattern of the connection names. By issuing this command, all connections with the names as Local Area Connection 1, Local Connection, and any connections with the names containing the word Local are effected.

/Release means to release the current IP configuration. After releasing IP, the network connection will have the ip addresss as 0.0.0.0. At this moment, your computer has no IP address. If you just leave it like this, your computer will try to broadcast DHCP Discover packet to find a new DHCP. It will take a little time.

If you want to have a new IP configuration immediately, issue this command

Asking for a new IP from DHCP

IPCONFIG /Renew

or

IPCONFIG /Renew “*pattern*”

examples: ipconfig /renew “*connection*” 

This command will renew IP configuration on any connections containing the word connection.

You would receive the same IP after renewing

You might notice that your connections have the old IP configuration as before you issuing the release and renew commands. This is normal because the IP you just released is still available for use on DHCP Server (I assume you have only one DHCP Server in your network). In a busy network, your recent IP could be issued to another clients, and you could acquire a new IP configuration.

In Part 2 of IPCONFIG command post, I will show some advanced usages of this command, such as DNS cache trouble shooting and configuring class ID.

About The Author

Hao Nguyen

Hao Nguyen

Hello! I'm Hao Nguyen and I'm currently working as a Network Engineer for a small firm in Houston. I enjoy writing technical documents and blog, such as PlanTutorials.com

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