How to connect remote destop on lan networking ?

Listed below is the general process which will need to be adjusted for your specific network situation.

On the target machine:

1. Enable Remote Desktop in System Properties.
2. Add remote user's account to Remote Desktop Users group.
3. If Windows firewall is enabled, enable Remote Desktop exception for the source host or subnet of the Remote Desktop connection. I don't recommend the default "any".
   
   
   - OR -
   
   If firewall other than Windows firewall is enabled, allow Remote Desktop connections to TCP port 3389 from the source host or subnet of the Remote Desktop connection.

Additionally, for access via Internet:
On Internet gateway router/device firewall serving the target machine's subnet, allow Remote Desktop connections to TCP port 3389 from the source host or subnet of the Remote Desktop connection. If target machine is on a privately addressed subnet behind a NAT-ing router, port forwarding to the machine will also need to be configured. Warning: Do this wrong and anyone, anywhere may have access to the target machine.

Further Info:

• See Frequently Asked Questions About Remote Desktop.
• A more secure approach for using Remote Desktop over the Internet is tunneling the RDP protocol through an IPSec or SSL based Virtual Private Network (VPN) or an encrypted Secure Shell (SSH) connection to a local remote access server on the target machine's network. A good explanation of the latter technique is Secure remote access of a private network using copSSH, PuTTY and Remote Desktop.