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Several connections at once

Posted: Fri Jul 17, 2009 8:12 pm
by AlexK
I noticed that Viscosity allows me to connect to several VPN connections at once. What is the benefit of that and what are the disadvantages? Why would I use such a setup and how does the OS know which connection to use?

Re: Several connections at once

Posted: Mon Jul 20, 2009 12:24 am
by James
Hi Alex,

Mac OS X uses its routing table to determine which VPN connection to send network traffic through. For example, if one of your remote VPN subnets has a route for all 10.0.0.x traffic, and another for 192.168.0.x traffic, Mac OS X will look at these routes and use the correct VPN connection. You can view your computer's routing table by opening the Network Utility application (under /Applications/Utilities/Network Utility.app), clicking on the Netstat tab, selecting "Display routing table information", and then click the Netstat button. You'll have to wait a few moments, and then your computer's routing table should be displayed.

Of course, you can run into routing conflicts when having multiple connections - it depends on how your connections are setup. And obviously, there can only ever be one default route (where all the traffic goes if there isn't a matching route).

Cheers,
James

Re: Several connections at once

Posted: Fri Aug 07, 2009 12:42 am
by AlexK
Hi James,

thank you for explaining. I see now that I don't really have a use for multiple connections (which is why it didn't make sense to me in the first place).