Hi,

I set up a ssh on one of my computers. My system setup is this: all my computers are on the same LAN, they all share the internet connection via a router. I registered a domain name with DynDNS which uses the ip address my isp assigned to me. On the internet, I can ssh to one of my computers, what do I need to do so that I can ssh to any computers on my LAN? Is it possible SINCE I only have one ip address from my isp?

B.Yes, there is a difference between outer IP and Local IP google it.Each one of your computer's have their own unique Local IP but, your router only has 1 outer IP and this is what the internet sees you as.Thanks for the reply.

There is no way to map the local ip to the external ip? And it also means I need to have different internet connection for each computer?

B.Are you running an SSH server on each of the different computers on the LAN?  If so, you can use your router's port mapping facility to send a different port to each different PC.

E.g.

External IP address: 80.74.134.12
Internal IP addresses: 192.168.23.10 to 192.168.23.15

SSH NORMALLY operates on port 22, so leave all the SSH servers set that way.

On the router, set it up so that:
incoming 80.74.134.12:1020 maps to 192.168.23.10:22
incoming 80.74.134.12:1021 maps to 192.168.23.11:22
incoming 80.74.134.12:1022 maps to 192.168.23.12:22
incoming 80.74.134.12:1023 maps to 192.168.23.13:22
incoming 80.74.134.12:1024 maps to 192.168.23.14:22
incoming 80.74.134.12:1025 maps to 192.168.23.15:22

Then, if you're using something LIKE PuTTY to connect to computer 192.168.23.13, you just tell it to go to IP address 80.74.134.12, port 1023.

Do you see what I mean?

The other way of doing it is to SSH into just the one PC, and then SSH to the other computers from there.  You only need one way in, after all.Thanks Rob, that's excatly what I want to do. so all I need is one DynDNS domain name. I will ry it out.

B.You got it.  Let us know how you get on?Hi,

I resurrected this question because I STILL can't find a solution to it.

Here is the set up. I have 4 PCs on the LAN, each has its own ip address. they are all connected to  a Linsys WRT54G router. I only have one external ip from COMCAST. What I like to do is to be able to ssh to a specific computer from a remote location. I have obtained an domain name from DynDNS. I can use this domain name to connect to one PC from a remote PC via the internet, but how can I specify which computer I want?

I tried to reconfigure the router so that it will forward the external ip to a specific internal ip but I screwed the router up the last time I tried. I am not sure what exactly I need to do. I guess I am not understanding the port mapping well. On this router it doesn't have port mapping but it does have one section come close to it called Advance Routing. I wonder if they mean the same thing? In case it helps, here is what the original routing table looks like.

I will appreciate any helps.

B.Nah, don't mess with the routing table.  What router is it?Hi,

It's a Linksys WRT54G router.

Right now, I can ssh to one computer on the ninternet, from that computer I can ssh to the other computer on the LAN.
There must be a prettier way to do this and it will be really nice if each computer on the LAN can have its own domain name. or something like this,

xyz.DynDNS.com [?] 192.168.1.101 --computer 1
xyz.DynDNS.com [?] 192.168.1.102 --computer 2
xyz.DynDNS.com [?] 192.168.1.103 --computer 3
...

Which means I need something to route the external ip to a particular internal ip. Is this called ip forwarding? ip routing? Can a router do that?

B.