Loading ...Howto: Ubuntu Linux convert DHCP network configuration to static IP configuration
My friend wanted to know how to change or convert DHCP network configuration to static configuration. After initial installation, he wanted to change network settings. Further, his system is w/o GUI system aka X Windows. Here is quick way to accomplish the same:
Your main network configuration file is /etc/network/interfaces
Desired new sample settings:
=> Host IP address 192.168.1.100
=> Netmask: 255.255.255.0
=> Network ID: 192.168.1.0
=> Broadcast IP: 192.168.1.255
=> Gateway/Router IP: 192.168.1.254
=> DNS Server: 192.168.1.254
Open network configuration file
$ sudo vi /etc/network/interfacesOR$ sudo nano /etc/network/interfaces
Find and remove dhcp entry:
iface eth0 inet dhcp
Append new network settings:
iface eth0 inet static
address 192.168.1.100
netmask 255.255.255.0
network 192.168.1.0
broadcast 192.168.1.255
gateway 192.168.1.254
Save and close the file. Restart the network:
$ sudo /etc/init.d/networking restart
Task: Define new DNS servers
Open /etc/resolv.conf file
$ sudo vi /etc/resolv.conf
You need to remove old DNS server assigned by DHCP server:
search myisp.com
nameserver 192.168.1.254
nameserver 202.54.1.20
nameserver 202.54.1.30
Save and close the file.
Task: Test DNS server
$ host cyberciti.biz
Network command line cheat sheet
You can also use commands to change settings. Please note that these settings are temporary and not the permanent. Use above method to make network changes permanent or GUI tool as described below.
Task: Display network interface information
$ ifconfig
Task: Take down network interface eth0 / take a network interface down
$ sudo ifconfig eth0 downOR $ sudo ifdown eth0
Task: Bring a network interface eth0 up
$ sudo ifconfig eth0 upOR$ sudo ifup eth0
Task: Change IP address and netmask from command line
Activate network interface eth0 with a new IP (192.168.1.50) / netmask:
$ sudo ifconfig eth0 192.168.1.50 netmask 255.255.255.0 up
Task: Display the routing table
$ /sbin/route OR$ /sbin/route -n
Output:
Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface localnet * 255.255.255.0 U 0 0 0 ra0 172.16.114.0 * 255.255.255.0 U 0 0 0 eth0 172.16.236.0 * 255.255.255.0 U 0 0 0 eth1 default 192.168.1.254 0.0.0.0 UG 0 0 0 ra0
Task: Add a new gateway
$ sudo route add default gw 172.16.236.0
Task: Display current active Internet connections (servers and established connection)
$ netstat -nat
Task: Display open ports
$ sudo netstat -tulpOR$ sudo netstat -tulpn
Task: Display network interfaces stats (RX/TX etc)
$ netstat -i
Task: Display output for active/established connections only
$ netstat -e
$ netstat -te
$ netstat -tue
Where,
- -t : TCP connections
- -u : UDP connections
- -e : Established
Task: Test network connectivity
Send ICMP ECHO_REQUEST to network hosts, routers, servers etc with ping command. This verifies connectivity exists between local host and remote network system:
$ ping router
$ ping 192.168.1.254
$ ping cyberciti.biz
See simple Linux system monitoring with ping command and scripts for more information.
Task: Use GUI (Graphical Configuration) network Tool
If you are new, use GUI configuration tool, type the following command at terminal:
$ network-admin &
Above command is Ubuntu's GUI for configuring network connections tool.
Final tip - Learn how find out more information about commands
A man page is your best friend when you wanted to learn more about particular command or syntax. For example, read detailed information about ifconfig and netstat command:
$ man ifconfig
$ man netstat
Just get a short help with all command options by appending --help option to each command:
$ netstat --help
Find out what command is used for particular task by searching the short descriptions and manual page names for the keyword:
$ man -k 'delete directory'
$ apropos -s 1 remove
Display short descriptions of a command:
$ whatis rm
$ whatis netstat
Linux offers an excellent collection of utilities, which can be use to finding the files and executables, remember you cannot memorize all the commands and files 
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You may also be interested in other helpful articles:
- Best Linux / UNIX Posts of 2007: Part ~ I
- Easy Linux or UNIX Network Load Testing
- Configure static routes in Debian or Red Hat Linux systems
- Ubuntu Linux: Creating ethernet alias for eth0 network device
- Quagga: Linux Dynamic Routing Software
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Tags: add_gateway, change_ip_address, dhcp, host_command, Linux, list_open_port, netstat_command, network, Networking, sudo_command, ubuntu
Thank you nixcraft!
You are not only teaching excellent networking specifics, but, most importantly, also making me understand how to do this on my own. Not too many guys out there are able to do this as you have done.
Thank you, this made it work for me. I had the problem of needing to use static ip address, for various other lan requirements.
Although, one minor glitch creeped up .. after I had edited the /etc/network file. My gateway is set to 192.168.1.1, rather than … 1.254, and so that is what I had set in the network file. After editing this file I still had no internet connection, but I could ping the gateway. But I was able to connect after modifying the setting in the gui: System–>Admin–>Network–>eth0–>gateway address. It had a default setting of 192.168.1.254, changing it to my actual gateway fixed it.
A very good tutorial. Thank you.
I have been struggling with networking for sometime. You have helped to clear up a lot of confusion.
Hi and thanks for this article.
Why do you change the 255 to 254 please?
Do I need to do that if setting a server box up within a network with other multiple OS’s?
NetworkManager is fine for varying wlan configurations. This guide gives a sleek way to configure a static network. Afterwards you can
apt-get –purge remove network-manager knetworkmanager network-manager-gnome dhcdbd
to get rid of unnecessarily runnig daemons.
[...] Howto: Ubuntu Linux convert DHCP network configuration to static IP configuration [...]
auto eth0 should precede anything added to “interfaces” and be on its own line.
one small problem… if you edit /etc/resolv.conf directly, the next time you ifdown or ifup an interface or reboot for that matter your settings are lost. In Ubuntu the resolv.conf is generated each time you up/down an interface. So unless you removed the resolvconf package which is generally installed by default, you need to add proper dns- entries to the /etc/network/interfaces file to make changes permanent. eg:
iface eth0 inet static
address 192.168.1.100
netmask 255.255.255.0
network 192.168.1.0
broadcast 192.168.1.255
gateway 192.168.1.254
# dns-* options are implemented by the resolvconf package, if installed
dns-nameservers 192.168.1.254
dns-search myisp.com
About dns-nameservers: if you have >1 dns servers they must be in 1 line separated by spaces. But not in 2-3 lines (it will hangup network startup script at all) !!!
I think only dhclient updates resolv.conf, look like ubuntu has some additional scripting at /etc/rc.d/*. On a side note, you can write protect resolv.conf
sudo chattr +i /etc/resolv.confman chattr
How can i encrypted the file from VI. And how can i connect the internet in my home and I want also connect the localarea network. And what is joe editor explane.
How can i configer the server connection on my one more system If i would like the 1st system is an Administrator…..
This was very useful to me cause i wasn’t able to find a way to accomplish that via dpkg-reconfigure or debconf.
thx for sharing
the polarizer
a litle tutorial to how to configure DHCP
dhcp
[...] อ้างอิง - Howto: Ubuntu Linux convert DHCP network configuration to static IP configuration [...]
how to i restart network
i used:
sudo /etc/init.d/networking restart
/etc/init.d/networking restart
bu still nothing happening,
pls can you help me.
How to save after changing something in the terminal window for ubuntu 7.04?
This was incredibly helpful. I am a very experienced Windows admin but I still feel like a newbie when it comes to Linux. Not only did I complete the task I needed with your help, you also made me realize the difference between editing config files and just using ifconfig.
Bookmarking your site.
I have just started with Linux with ubuntu server 8.94. Never used Linux before.
Just wanted to say thank you. Wanted to use Fixed Ip for the server and found your site and great instructions easily.
Just wanted to say thanks.
Excellent. Thanks.
Oh wow. Thank you so much for this tip!