1
... and I open a browser....
Who decides which network connection to use? Or is it intelligent or random? Is this decision made for each request, for each application session, or for each something else?
Does this mean that if I want to connect a second (or third) connection to the Internet, I should restart all my apps or I should log off and log back in?
I'm using Windows.
William C
Posted 2011-09-01T05:16:27.220
Reputation: 2 149
1
IP routes have "metrics", which can be used as an order value for otherwise equivalent routes. Most operating systems try to assign those intelligently – for example, if you can access the Internet over both wired Ethernet and wireless WiFi, you will have two "default" routes, but the wired one will have a lower metric and will be preferred.
$ ip -4 route default via 192.168.1.254 dev eth0 proto static 192.168.1.0/24 dev eth0 proto kernel scope link src 192.168.1.115 metric 1 192.168.1.0/24 dev wlan0 proto kernel scope link src 192.168.1.183 metric 2
(This is not a very good example, since both eth0 and wlan0 are connected to the same network, with the same default gateway. With multiple ISPs, you would see two default routes.)
On Linux you can list routes by ip route or route -n; on Windows – route print.
user1686
Posted 2011-09-01T05:16:27.220
Reputation: 283 655
Hi. Do you perhaps know how often these metrics are remeasured/recalculated? In Windows? – William C – 2011-09-02T04:07:57.090
Only when the user changes them, or when the interface disappears/reappears. There is no measuring involved, just a few simple rules (which I have no idea of). – user1686 – 2011-09-02T05:06:08.473
1
Hosts have a single default route. Generally it will use only one. A router can be configured for failover, but still any connection will use only one path.
Keith
Posted 2011-09-01T05:16:27.220
Reputation: 7 263
Yes multiple ISPs. – William C – 2011-09-01T06:26:57.160
0
When I tried to use ForceBindIP and opened Firefox without forcing it to use one of the connections, it used the last one that an app was forced to use.
I believe Windows makes the last used network connection to default for apps to use when not being forced to use a specific one, at least that's what happened to me.
Nexerus
Posted 2011-09-01T05:16:27.220
Reputation: 798
1what do you mean by "connections to the Internet"? Multiple ISPs? – Keith – 2011-09-01T05:31:36.960
Yes multiple ISPs. – William C – 2011-09-01T06:26:44.803
To one router? or two routers? What is your network topology? – Keith – 2011-09-01T06:47:24.743
@Keith: Two network adapters, two ISPs, no routers. – William C – 2011-09-02T04:01:56.387