+ 0 Votes Most VPN clients enforce a non-split tunnel robo_dev Updated - January 14, 2013 at 2:13am PST Thus ALL communication must go over the defined tunneled VPN interface. Some applications do not behave properly, like they look to connect to a licensing server, or try to establish connectivity over an unexpected port or protocol. If the computer works Ok on the LAN, then ANY ports and protocols are allowed, and ANY interface can be used. When the application is working properly, goto a command prompt and type netstat, this tells you what connections are established at what ports. Also type netstat -b This tells you what process or program is doing the communication. Now if you do the same command when the VPN is established, compare the two results...this will give some clues as to what is wrong. For example, some VPN clients add what are essentially firewall rules (e.g. no split tunneling), so if the port/protocol is being blocked, then the app will not work.