I am constructing an ip-ip tunnel between remote linux server and the local windows server.
The windows server does not support raw ip-ip tunnel so I develop a simple app which makes usage of wintun.
Said the local windows server is bound to ip_local, the remote linux server is bound to ip_remote, and the tunnel ip is ip_tun.
Currently, the windows server can receive the incoming packet (outer ip_remote->ip_local, inner ip_client->ip_tun) from the remote linux server in the tunnel.
For the outgoing packet (ip_tun->ip_client), if I route the packet to the tun NIC, the packet can be sent out.
However, if I route the packet to the real NIC, the packet is ignored.
Thus there seems a mechanism that blocks the sending of packets when the source ip is not bound to the corresponding NIC. (In the above case, because ip_tun is not bound to the real NIC, the outgoing packet is ignore.)
Is there any configuration that can disable such mechanism? Thanks for any help.
