How to change server IP address from DHCP to static?
1. Gather the required information
Static IP addresses are assigned for network interfaces. You can find out all your network interfaces names using this command:
ifconfig
You have to pick the one that has the address you already know. For example we have a server with such interfaces:
eth0 Link encap:Ethernet HWaddr 00:22:15:98:30:27 inet addr:192.168.0.108 Bcast:192.168.0.255 Mask:255.255.255.0 inet6 addr: fe80::222:15ff:fe98:3022/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:491112 errors:0 dropped:0 overruns:0 frame:0 TX packets:452621 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:553199357 (527.5 MiB) TX bytes:48077932 (45.8 MiB) Interrupt:24 Base address:0x6000 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:7039 errors:0 dropped:0 overruns:0 frame:0 TX packets:7039 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:1892466 (1.8 MiB) TX bytes:1892466 (1.8 MiB)
We see that current IP address is 192.168.0.108, network mask: 255.255.255.0
DNS settings are located in a configuration file /etc/resolv.conf:
bash-4.1$ cat /etc/resolv.conf # Generated by NetworkManager nameserver 213.197.128.71 nameserver 213.197.150.130
2. Change IP address to static
Open a configuration file with a desired Linux editor (for example nano, mcedit, vi) which matches your network interface name, in this example we will use eth0:
mcedit /etc/sysconfig/network-scripts/ifcfg-eth0
You will see a configuration file like this:
DEVICE="eth0" BOOTPROTO="dhcp" HWADDR="00:22:15:98:30:27" NM_CONTROLLED="yes" ONBOOT="yes"
You have to change it to look like this:
Warning!!! You must be sure that the settings below are correct or you will shoot yourself to the leg - you will be disconnected and will not be able to connect again when configuring remotely
DEVICE=eth0 BOOTPROTO=none ONBOOT=yes HWADDR=00:22:15:98:30:27 # <-- !!!!leave this setting as is in your current configuration, it will be different than provided here!!! NETMASK=255.255.255.0 # set here your netmask IPADDR=192.168.0.22 # set here your desired STATIC IP ADDRESS GATEWAY=192.168.0.1 # set here your desired Gateway address TYPE=Ethernet USERCTL=no IPV6INIT=no PEERDNS=yes
Warning!!! You must be sure that the settings above are correct or you will shoot yourself to the leg - you will be disconnected and will not be able to connect again when configuring remotely
3.Restarting the network
When you are sure that you set up the network correctly - save the changes to an opened file and restart your server networking using this command:
/etc/init.d/network restart
Other settings that have to be changed
When changing the server address you also must make additional changes documented here