Cannot connect to Plesk via FTP: unknown configuration directive 'IdentLookups'

Symptoms

1. ProFTPD package was installed/updated from the Atomicorp repository:

   CONFIG_TEXT: # rpm -qa | grep proftpd
   psa-proftpd-1.3.7rc3-3.el6.art.x86_64

   CONFIG_TEXT: # rpm -qi psa-proftpd-1.3.7rc3-3.el6.art.x86_64 | grep Vendor
   Version : 1.3.7rc3 Vendor: Atomicorp

2. Connection to the server via FTP fails:

   CONFIG_TEXT: Status: Connecting to 203.0.113.2:21...
   Status: Connection established, waiting for welcome message...
   Error: Could not connect to server

   OR

   CONFIG_TEXT: 421 Service not available, remote server has closed connection

3. proftpd -nd10command fails with error in /var/log/messages:

   CONFIG_TEXT: 2020-01-01 12:00:00,202 example.com proftpd[29943]: fatal: unknown configuration directive 'IdentLookups' on line 90 of '/etc/proftpd.conf'

Cause

Atomicorp ProFTP service is not compiled with the mod_ident.c module.

The fix was released by Atomicorp on version psa-proftpd-1.3.7rc3-6.el6.art.x86_64.

Resolution

1. Log in to Plesk via SSH

2. Update the ProFTPD package to psa-proftpd-1.3.7rc3-6

   # yum update psa-proftpd