The issue happens when user runs snds listener command while sdns is off. If commands are ran in that sequence the /etc/usercfg/etc/namedb/named.conf file does not include local/listen.conf file and allows to listen on port 53 on all ip, instead of allowing only listeners ips.

Fixed by making sure to include lietener.conf when sdns on is run by checking if listeners are already configured.

run sdns on and sdns listerner on made sure only can telnet to lister ip on port 53.

2 add listener first, then turn on snds (this case used allow all ip to listen on port 53)made sure only can telnet to lister ip on port 53.