Tftp

IP6M uses Atftpd package for tftp service. Since Atftpd doesn't support IPv6, we need Xinetd to run it.

Installing atftpd:

sudo apt install atftpd

Xinetd configuration (/etc/xinetd.d/tftp) for Atftpd is the following:

service tftp
{
    socket_type  = dgram
    protocol     = udp
    port         = 69
    wait         = yes
    user         = www-data
    server       = /usr/sbin/in.tftpd
    server_args  = /var/www/drupal8/private/tftp
    disable      = no
}

Most interesting option is the "server_args" option, that points to the private files directory under the Drupal instance. This is where the Drupal application creates the cable modem configuration files, and atftpd serves them to cable modems.