For cPanel & WHM version 68
Overview
Warning:
We strongly recommend that you only perform these actions on a new installation of cPanel & WHM. Do not attempt a 1:1 NAT configuration on an existing production server.
When you install cPanel & WHM, the installer will detect whether your server is on a NAT-configured network. If the installer detects a NAT-configured network, your server will configure itself for NAT mode and attempt to automatically map local IP addresses to public IP addresses.
Notes:
- If you use a NAT environment, your server must reside in a 1:1 NAT configuration to install cPanel & WHM.
- For a list of ports that you must open to allow cPanel & WHM services to function on your server, read our How to Configure Your Firewall for cPanel Services documentation.
The mapping process
The system attempts to map all non-loopback IP addresses bound to any network interface on the server to a public IP address.
To complete this process, the system performs the following actions:
- Your server will send an outgoing connection from each local IP address to the
http://myip.cpanel.net/v1.0/server. - The
http://myip.cpanel.net/v1.0/server responds with the public IP address from which it received the request. - The system maps the local IP address to this public IP address.
Warning:
We do not recommend that you map more than one local IP map address to a single public IP address.
Manage IP addresses
You can manage the maps for local and remote IP addresses with the following WHM interfaces:
- Add a New IP Address (WHM >> Home >> IP Functions >> Add a New IP Address)
- Show or Delete Current IP Address (WHM >> Home >> IP Functions >> Show or Delete Current IP Address)
Each interface displays the warning notice NAT mode enabled if NAT is enabled on your server.
Warning:
If multiple local IP addresses match the same public IP address, the system will only map the first local IP address in the /var/cpanel/cpnat file.
The build_cpnat script
The build_cpnat script uses the http://myip.cpanel.net/v1.0/ server to map local IP addresses to public IP addresses. However, if you wish to use a different IP address lookup service, open the /etc/cpsources.conf file with a text editor and add the following line:
MYIP=http://myip.cpanel.net/v1.0/
For more information about the build_cpnat script, run the following command:
/scripts/build_cpnat --man
Notes:
- If you accidentally delete your
cpnatfile or the file becomes becomes corrupted, rebuild it with the/scripts/build_cpnatscript. - The
/var/cpanel/cpnatfile acts as a flag file for NAT mode. If the installer mistakenly detects a NAT-configured network, delete the/var/cpanel/cpnatfile to disable NAT mode.
Additional documentation