Comments on: Reverse SSH tunnel or connecting to computer behind NAT router

By: Neil

Neil — Mon, 09 Jan 2012 12:15:11 +0000

thanks! is it ok to run ssh -R 6333:localhost:X user_on_server@server as a cron job?

By: jobs in graphic design

jobs in graphic design — Thu, 17 Feb 2011 16:11:13 +0000

I absolutely accept what you have stated. In fact, I browsed through your other articles and I do believe you are completely correct. Great job with this online site.

Reply - Quote

By: Rahul Panwar

Rahul Panwar — Sat, 09 Oct 2010 18:16:51 +0000

@Alexander Sandler - Thanks for giving this information, i was always using it through a firewall. But i will definitely try it without any firewall. ;)

Reply - @Alexander Sandler<\/a> - Thanks for giving this information, i was always using it through a firewall. But i will definitely try it without any firewall. ;)'); return false;">Quote

By: Alexander Sandler

Alexander Sandler — Sat, 09 Oct 2010 09:12:01 +0000

@androidx219 Yes, I am sure about it. I don't know how you used their products before. Hamachi creates P2P connection. @Rahul Panwar I am afraid you're mistaken. Hamachi creates P2P connections. If it cannot bypass firewall it will drop do relay mode (with server in the middle, like you described). Naturally relay mode is very slow. However, normally it will be P2P.

Reply - @androidx219<\/a>\r\nYes, I am sure about it. I don\'t know how you used their products before. Hamachi creates P2P connection.\r\n\r\n @Rahul Panwar<\/a>\r\nI am afraid you\'re mistaken. Hamachi creates P2P connections. If it cannot bypass firewall it will drop do relay mode (with server in the middle, like you described). Naturally relay mode is very slow. However, normally it will be P2P.'); return false;">Quote

By: Rahul Panwar

Rahul Panwar — Wed, 06 Oct 2010 17:43:39 +0000

@androidx219 - @androidx219 - Logmein client creates a connection with a remote public server & that remote public server connect your system to other system. It is not P2P.

Reply - @androidx219<\/a> - @androidx219<\/a> - Logmein client creates a connection with a remote public server & that remote public server connect your system to other system. It is not P2P.'); return false;">Quote

By: androidx219

androidx219 — Thu, 30 Sep 2010 23:03:43 +0000

@Alexander Sandler - Are you sure that logmein enables the computers establish a p2p link. I had used logmein earlier and i could not see the remote computer's nat/external ip in my connection list (using tcpview in windows) when using the remote desktop feature. May be i did'nt notice carefully, i used it long back. If it really helps establishing a p2p link then its great.

Reply - @Alexander Sandler<\/a> - \r\nAre you sure that logmein enables the computers establish a p2p link. I had used logmein earlier and i could not see the remote computer\'s nat\/external ip in my connection list (using tcpview in windows) when using the remote desktop feature. May be i did\'nt notice carefully, i used it long back. If it really helps establishing a p2p link then its great.'); return false;">Quote

By: Alexander Sandler

Alexander Sandler — Sun, 26 Sep 2010 21:23:14 +0000

@Hale There's no way to establish p2p connection bypassing NAT/firewall without some serious TCP magic. I know one application that does this kind of magic. It's called hamachi (logmein.com).

Reply - @Hale<\/a>\r\nThere\'s no way to establish p2p connection bypassing NAT\/firewall without some serious TCP magic. I know one application that does this kind of magic. It\'s called hamachi (logmein.com).'); return false;">Quote

By: androidx219

androidx219 — Fri, 17 Sep 2010 13:38:49 +0000

@Hale - After the remote connection is established by the above described method, you may either have shell access (X=22) or vnc type remote access (X=5900) to office computer whatever you prefer. Now you can use this connection to establish a new connection directly from office computer to the home computer by using the IP of your home computer/router (with appropriate port forwardings in case you use a router). You may use the ssh service of the home computer or whatever service you might like to use. Once this new p2p connection is established, the previous indirect connection can be terminated. I dont think there is any other way to accomplish direct connection in this type of a setup.

Reply - @Hale<\/a> - \r\nAfter the remote connection is established by the above described method, you may either have shell access (X=22) or vnc type remote access (X=5900) to office computer whatever you prefer. Now you can use this connection to establish a new connection directly from office computer to the home computer by using the IP of your home computer\/router (with appropriate port forwardings in case you use a router). You may use the ssh service of the home computer or whatever service you might like to use. Once this new p2p connection is established, the previous indirect connection can be terminated.\r\nI dont think there is any other way to accomplish direct connection in this type of a setup.'); return false;">Quote

By: Hale

Hale — Fri, 17 Sep 2010 03:49:16 +0000

Is it possible to make the home pc and office pc to communicate directly? I mean, after the remote connection is established, the data goes p2p?

Reply - Quote

By: Vinod

Vinod — Wed, 15 Sep 2010 23:03:40 +0000

Hey Alex, Liked your article on reverse ssh tunneling. It was really useful for a problem I'm trying to solve. I have a question though. How do we keep the reverse-ssh tunnel active? As I see it, a "ServerAliveInterval" will only keep-alive the forward connection, not the reverse? Wouldn't the NAT block the reverse channel, if there is no traffic for some time? And since, a since a reverse SSH tunnel doesnot actually setup a ssh connection in the reverse direction (unless someone connects), even a "ClientAliveInterval" doesn't work? thanks, Vinod

Reply - Quote