A Netlink error occurred: Operation not supported. cpsrvd service unable to start

Symptoms

cPanel will not start, and running the restartsrv_cpsrvd script returns an error similar to one of the following.

Cpanel::Exception::Netlink/(XID x4zxbc) A Netlink error occurred: Operation not supported

send: Connection refused at /usr/local/cpanel/Cpanel/Linux/Netlink.pm line 150.

Description

This issue can occur with older kernels or when the kernel is compiled with incorrect modules. If updating the kernel doesn't allow cPanel to start, creating the kernel_does_not_support_modern_ipv4_socket_options touch file will allow cPanel to start.

Workaround

1. Access the server's command line as the 'root' user via SSH or "Terminal" in WHM.
2. Run the following command to create the touchfile.

   touch /var/cpanel/kernel_does_not_support_modern_ipv4_socket_options

3. Start cPanel.

   /usr/local/cpanel/scripts/restartsrv_cpsrvd --start