like most i had a problem getting connected to my server from external IP's
thru my router.
this is what i found that worked for me.

forward your ports on your router
udp 9987
tcp 10011
tcp 30033

while in your router, look to see what internal IP it assigns to the computer
your TS3 server is on.
my computer gets an internal IP from router of 192.168.1.4
so my command line is..
\\ts3server_win32.exe" voice_ip=192.168.1.4 query_ip=192.168.1.4 filetransfer_ip=192.168.1.4

for an .ini file


machine_id=
default_voice_port=9987
voice_ip=192.168.1.4
licensepath=
filetransfer_port=30033
filetransfer_ip=192.168.1.4
query_port=10011
query_ip=192.168.1.4
dbplugin=ts3db_sqlite3
dbpluginparameter=
dbsqlpath=sql/
dbsqlcreatepath=create_sqlite/
logpath=logs
logquerycommands=0

hope it helps