running putty ssh sessions on ubuntu server

Maybe there's some problem with the specific port you've chosen (57757). Is the port specified for the LAN side correct? That is, assuming you haven't changed the SSH server's configuration, is port 57757 on the WAN side set to forward to port 22 on the OpenSSH server? (You may want to double-check this.) then you'll have to do some troubleshooting.

If that turns out not to have been the problem. So you can most likely fix this by making sure the port is being forwarded to the correct IP address on the LAN. That causes exactly the situation you've described. When you forward a port to a nonexistent machine with a NAT router, it sends incoming traffic on that port to the nonexistent machine, which is to say that it sends it into a black hole it is effectively dropped. in any case, you can connect to port 22 on the LAN, so it's open.unless you've changed firewall settings (e.g., ufw, iptables), no ports are filtered, and.If ports were filtered by a firewall, then you'd get what you're seeing-no response to a connection attempt.

reject the connection attempt, if the port is closed.accept the connection, if the port is open.So unless you've changed firewall settings in Ubuntu, an attempt to open a connection to any TCP port, 1 through 65535, will either: Your NAT router receives incoming traffic on port 57757, and sends it to a particular IP address and port on the LAN.īy default, Ubuntu doesn't filter incoming connection attempts with a firewall. Usually this means you've forwarded the port to the wrong IP address on the LAN.

Running putty ssh sessions on ubuntu server