I configure a static NAT on a cisco 1841.
below is the config.
ip address 213.X.X.X 255.255.255.240
ip nat outside
ip address 192.168.X.X 255.255.255.0
ip nat inside
ip nat inside source static tcp 192.168.X.Y 5101 213.X.X.Y 5101
When i telnet from my local network to 192.168.X.Y i have a result.
When i telnet from out side my network on 213.X.X.Y 5101 i have the following:
Could not open connection to the host, on port 5101: Connect failed
But when i telnet from outside to port 25 or 110 i have a result.