the strangest connection issue

[tremendousb]

i have a server running. i connect to the internet through an adsl router called "actiontek". the computers on our network are able to connect to it locally using our local ip. i have friends who can connect to it over the internet using the non-local ip (not sure what its proper name is). but then disaster strikes: one person cannot connect to us. he can, however, connect to other teamspeak servers we tried. but he gets the "error" with the "server isn't running" or whatever. what could the problem be?

thanks very much

also, his sound is choppy - his light flashes on and off - when he's on servers he can connect to. sound is also choppy when he is on push to talk. what could the problem here be?

thanks again

-bart

[tremendousb]

update to the guy's choppyness problem:
in windows, if he unmutes his mic he can hear himself in his speakers fine. in teamspeak, if he goes to local test mode he hears himself choppy. his computer is fast, so that's not the problem. he has tried wave and direct sound and they both sound the same. he also says the problem is the same in ventrilo.
any ideas?

[Brain]

Regarding the choppiness: That sounds suspiciously like a sound card driver problem.
And regarding your network structure: You basically have a NAT-router and a handful of computers connected to your LAN via switches, hubs and the integrated switch/hub in the NAT-router, is that about right?
And this one guy is someone from within your LAN, did I understand that correctly?

[tremendousb]

you have the network scenario right. but the guy with the choppiness problem is not on our network. and to make it super clear, he can't get on our server. this problem is on other servers which he can connect to.

he has just updated his drivers and the problem remains