[ Date Index ] [ Thread Index ] [ <= Previous by date / thread ] [ Next by date / thread => ]
Grant Sewell wrote: > On Fri, 27 Feb 2009 09:44:36 +0000 > dave wrote: > > >> When EntaNet bothered providing a connection I had a static IP >> address, and from outside I could simply ssh tunnel into it. However, >> with mobile broadband they use their own NAT somewhere in their >> network. Does anyone know a solution to this? Skype works okay, so >> there is obviously a technique that punches through their and my NAT, >> but I don't know how to ssh in, short of setting up a reverse tunnel >> to an external machine. That would provide another point of failure, >> and slow the connection further. >> > > I believe Skype works because both ends need to communicate with > Skype's own server and that handles the traffic at both ends... hence > wh you can't use Skype on an internal network that has no Internet > connectivity. > > Grant. > > It sets up the initial communication talking to a third party, but then sets up peer-to-peer comms for the speech traffic. VoIP with SIP / RTP does the same. To do this it needs to punch a hole through the firewall. There are various techniques to do this, but Skype seems to be very good at it. This is all UDP. There are techniques for punching through firewalls with TCP, which I would need for ssh, but they are more complex. NAT is great until you want p2p through it. http://www.linuxjournal.com/article/9004 D -- The Mailing List for the Devon & Cornwall LUG http://mailman.dclug.org.uk/listinfo/list FAQ: http://www.dcglug.org.uk/linux_adm/list-faq.html