Adding IP will bring down the server

abubin

Well-Known Member
Dec 7, 2004
401
3
168
This is really strange. This is the first CentOS 7 server we are using with cpanel. Yesterday, we found out that when we add a new IP into the server, it will bring down the server. Or at least the networking part of the server. We ended up unable to remote or access into the server through network. We called our DC and they say screen is still showing linux login page.

Once the server is rebooted, server will be accessible again. We can then access the server through main IP. However, secondary IP is not accessible. The problem is, after about 10-15 minutes, the whole network is down again. As we are not physically at the DC, we cannot login locally to check the problem. We had to request for a reboot and then go in to remove the extra IP before network go down again.

This is really strange. We use cpanel to add the IP and we have done this many times without issue on cpanel installed on centos 5 and 6.

Googling, we did not find anyone else have this issue. Anyone can help?
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
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Hello @abubin,

Could you open a support ticket using the link in my signature so we can access the server to take a closer look at what's happening? You can post the ticket number here so we can update this thread with the outcome.

Thank you.
 

abubin

Well-Known Member
Dec 7, 2004
401
3
168
A
Hello @abubin,

Could you open a support ticket using the link in my signature so we can access the server to take a closer look at what's happening? You can post the ticket number here so we can update this thread with the outcome.

Thank you.
As I got the cpanel license from a vendor, I will need to get support from them first. I will update here once they response. Meanwhile if anyone have any idea, please do discuss here. Thanks.
 
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abubin

Well-Known Member
Dec 7, 2004
401
3
168
after spending few days with the cpanel vendor support. We still have not resolve this issue.

However, we do find out that as below:
- we have 2 interface running in the server enp0s25 and enp2s0.
- enp0s25 is running with IP 127.0.0.1
- enp2s0 is running with a valid main IP 1.2.3.4
- however, when we create IP in WHM, somehow cpanel will create it on interface enp0s25. So this IP will not work as that interface does not have a physical line connected to it.
- I have tried removing NetworkManager and also disable interface enp0s25 (ifdown enp0s25) but still when adding IP will go to that interface.

Any idea how I could make cpanel recognize interface enp2s0 as the main interface?
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
47,908
2,216
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Any idea how I could make cpanel recognize interface enp2s0 as the main interface?
Hello,

You can update the following option under the "Basic Config" tab in "WHM Home » Server Configuration » Basic WebHost Manager® Setup":

The ethernet device onto which new IP addresses are added. Devices detected with at least one IP are listed in the drop-down, or you may specify another device.

Thank you.
 

abubin

Well-Known Member
Dec 7, 2004
401
3
168
Hello,

You can update the following option under the "Basic Config" tab in "WHM Home » Server Configuration » Basic WebHost Manager® Setup":

The ethernet device onto which new IP addresses are added. Devices detected with at least one IP are listed in the drop-down, or you may specify another device.

Thank you.
yup that is exactly how to fix it. Thanks for the info.

However, it is strange that it was set to this network interface that is not even being used. It could be a glitch in cpanel setup or could be a mistake from our side when we setup the server. Regardless, I am glad that it is solved. Hope this will help someone else who is having similar issue.
 

cPanelMichael

Administrator
Staff member
Apr 11, 2011
47,908
2,216
463
However, it is strange that it was set to this network interface that is not even being used. It could be a glitch in cpanel setup or could be a mistake from our side when we setup the server. Regardless, I am glad that it is solved. Hope this will help someone else who is having similar issue.
Hello,

You may want to check with your data center or hosting provider to see if the ethernet device name was changed on their side, as that appears to be the most common reason for this issue.

Thank you.