Using Ssh In A Vpn Need details about Virtual Private network

[longtimeago 0]

Hello every one , if there is a single large network and the Admin has gone for setting up a Virtual private network , let me consider this scenario as network a and network b , Both the networks a and b belong to a single network , but they are put under diffrent VPN ( Virtual private network ) , both the networks are assigned into diffrent VPN from a Layer 3 Switch ( A Cisco's product ) and in this layer 3 switch the admin have made some conifuration to put both a and b under diffrent subnets.I am not that much familiar about this VPN concept , but now i do find that these networks are not seperated completly though they are under diffrenet VPN , if some one hosts a webserver in network A and shares a file , and another person can use a PUTTY CLIENT ( SSH Tunneling client ) in network B and through this putty client once can bypass the VPN restriction and can access the file from network A .So actually here the main aim of the network admin is to split two networks , but out of practical experience i am writing that there is a way possible to bypass the VPN . So network Admins beware ,Now my question for you is this , if one is able to bypass this VPN with SSH tunneling , why not one can use the other network ?? Let me be more clear , if Network A has a high privelage and Network B has comparitively less provelage ( may be the connections are made through a proxy server and many sites are blocked in the proxy server ) , in such a case a person in Network B can use the Same connection as in Network A with SSH Tunneling , but for this some configurations has to be done so if anyone is confident about the connection settings for a SSH Tunneling client in this scenario , like what config. has to be done to the SSH client etc. please share it here , so that many can beaware of the security policies .