xterm failed while vpn

[Nina Pham]

our company linux server is running pptpd service, I vpn in to this 
server from my XP pc at home and tried to xterm(using exceed and rlogin 
protocal ) to it. It didn't display anything. However, with vpn 
connection, I can xterm to other server. I searched on the internet and 
some people also have this problem, but it's not resolved yet. Did I 
make a mistake with the configuration?