A few things:
- Don't use
telnet - prefer something more secure like
- Are you both on the same network?
- It sounds like you're confusing 'internal' and 'external' IP addresses.
- If you are both on the same network, and are happy with not having access to the machine from outside of your network, then do not touch your router, and do not look at port forwarding.
Public vs. Private IP Address
Most home networks (and many larger networks) will use something called Network Address Translation (NAT). This means that a single public IP address is used to provide access to the internet for the whole network. A public IP address is accessible via the internet.
Private IP addresses are accessible only within a closed, 'private network'. They are in the defined ranges (below). Any address in these ranges will not be accessible over the internet.
The computer will report your 'private' address, while external servers that you connect to (e.g: Google) will see your 'public' address.
Connection between computers
As mentioned above, if you are both sitting on the same network (it's generally okay to assume that if Google reports the same public IP to both of you, then you're on the same network), then you do not need to send data via the internet to communicate between your computers.
You said that the connection 'hangs', and this could be due to a few things (it's better to leave it to report an error than cancelling the program).
- You are on different networks, but happen to share a private network address range... no device is at that address on your network, so the connection will timeout and fail.
- You are on different networks, and are on different private address ranges... your computer will forward the packets to the router, who (if configured properly) should not forward them to the internet... the connection will be 'unroutable' and fail, or will timeout and fail.
- You are on the same network, but her computer has a firewall running, and is configured to ignore these packets... the connection will timeout and fail