FTP service fails to start on a Plesk server with the following error:
xinetd: socket creation failed (Address family not supported by protocol (errno = 97)). service = ftp
xinetd: Service ftp failed to start and is deactivated.
The issue is caused by disabled IPv6 support on the host:
# grep -r ipv6 /etc/modprobe.d/
alias ipv6 off
options ipv6 disable=1
# grep -i v6 /etc/sysconfig/network
Connect to the server via SSH.
Replace the IPv6 value by IPv4 in the
/etc/xinetd.d/ftp_psafile as shown in the example below. For this, edit the file in any text editor, for example, in the vi editor:
flags = IPv6 <== REMOVE
flags = IPv4 <== ADD
disable = no
socket_type = stream
protocol = tcp
wait = no
user = root
instances = UNLIMITED
server = /usr/sbin/in.proftpd
server_args = -c /etc/proftpd.conf
Note: this change could be rewritten after the Plesk upgrade
Save changes and close the file.
# systemctl start xinetd