I just disabled IPv6 completely - the network is v4 only anyway -
resulting in these netstat output:
Proto Recv-Q Send-Q Local Address Foreign
Address State PID/Program name
tcp 0 0 0.0.0.0:389
0.0.0.0:* LISTEN 2623/ns-slapd
tcp 0 0 0.0.0.0:636
0.0.0.0:* LISTEN 2623/ns-slapd
remote clients cannot connect anyway, nmap states the port not open :(