Question : Problem: VPN connection fails occasionally !

What happens is that when trying to dial VPN from one of the PC's on the LAN, i succeed occasionally to establish the connection, but in most cases connection fails and what i feel is that the time out value of the VPN server is not letting me to accomplish the process successfully since it works once and fails most of the time especially when the LAN's bandwidth is highly utilized ( congestion )........Is it that the VPN server on the other side of the world requiring authentication in a short period of time that i cannot reach due to the lack of internet bandwidth shared on the network ??? Is there any other reason that could be behind the occasional failure ?? What are the initial steps, or any workaround on the clients PC to improve VPN connectivity response ??

Please advice.

P.s ( when i used a separate ADSL line ( no bandwidth shared with other PCs) i never faced a single login failure to the same VPN server, from same PC )

Answer : Problem: VPN connection fails occasionally !

By default, all out going ports are open and all incoming ports are closed.
 
Perhaps we need a little more information. Could you outline your VPN configuration, from where you are trying to establish the connection and what error message/# you receive when the connection fails. i.e is this a VPN software client to VPN router connection, site to site, or client to VPN server such as a Windows VPN server? Also what make router and VPN client are you using? Sounds like a Cisco software client to Cisco PIX VPN ?