I have a program which uses TCP connection for VPN tunnel. How do i Change TCP tunnel to UDP tunnel?..
VPN is an IP level facility so you are not generally in need of a tunnel on it. You can tcp or udp on it, unless some firewall in the path blocks it. Then you might be interested in an ssh tunnel for tcp, but ssh does not support udp. You can make proxies move udp packets through the tcp ssh tunnel: udp over ssh tunnel