CentOS ifcfg-eth0 config file deleted. Utility to recreate it?

Question

On CentOS I no longer have a ifcfg-eth0 configuration file (I deleted it). When I run system-configure-network it shows no interfaces that I can edit. How can I recreate the ifcfg-eth0 configuration file? (Like the CentOS installer does)

I can manually do a: ifconfig eth0 192.168.0.199 and then a ping 192.168.0.1. But that's not the proper way. How can I do it using the CentOS network scripts?

I prefer not to do this by hand as there are many hardlinks and confusing stuff. I am new to CentOS.

Solution 1

There might be a utility, but I don't know what it is. You can just create a file at /etc/sysconfig/network-scripts/ifcfg-eth0 with contents similar to:

DEVICE=eth0
BOOTPROTO=static
ONBOOT=yes
IPADDR=192.168.0.199
NETMASK=255.255.255.0
GATEWAY=192.168.0.1

Solution 2

I use the command: system-config-network-tui

Creating the file by hand is a good answer too, but this will get the MAC address for you.

Solution 3

This may not be valuable anymore to the asker but for someone else, if you have the gui running you can go to System > Preferences > Network Connections and a window will open. Now if you see a device listed there then click on it and just make some edit and save and the file will appear. If no device is listed (will be rare and only if you aren't getting internet connectivity) then you can simply click add and name it eth0 or whatever you like and click save. No need to edit anything, it'll automatically do it all for you.

PS: the file ifcfg-"NAME" is the name you give it in the network connections window when you created it.

Solution 4

So this Worked for me.

History:

• I added a new Virtual Network card, whose ifcfg-eth2 file was not generated after a re-boot.

• I navigated the the network-scripts directory and ran the commands in the below sequence.

  # cd /etc/sysconfig/network-scripts
  # ./net.hotplug
  # ./ifup-eth
  # ifup eth2
  -- the ifcfg-eth2 file was generated at this point, but was missing the "HWADDR" field --
  
  # system-config-network
  -- Select your Device and edit settings if needed, before saving the settings --
  -- After saving the Configuration settings, the "HWADDR" filed was added as well --
  

Solution 5

There is a utility called sysconf-network or something like that to allow you to manager the network connections. That is a command line utility.

Here is a link to the FAQ about their /etc/sysconfig system.

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Comments

[unixman83]

Running system-config-network seems to be a good idea after recreating the ifcfg-eth0 file.

[Stefan Lasiewski]

This answer neglects to mention the HWADDR= field which contains the MAC address of the device. This step is one of the bigger pain points of creating ifcfg-ethN by hand.

[Trevor Boyd Smith]

For me I don't edit these files enough to create from scratch but I can more easily edit one that exists. So this utility is way faster than needing to googling until I find a trusted example. In my case it missed the ONBOOT=yes value so I still had to edit but it was much better than handwriting the whole thing from scratch.

[knb]

On Centos 7, use nmtui

[Admin]

On CentOS 7.9 it works too. Started nmtui -> Edit a connection -> selected ethX with missing ifcfg-ethX file in /etc/sysconfig/network-script -> Edit -> In my case I wanted automatic connect -> OK -> Back (exit the program), the result, ifcfg-ethX was created. I have checked the content, looks ok.