Post date: Jul 4, 2011 2:25:09 PM
If you have multiple gateways and you would like to be able to fail over between them based on when the upstream internet connection feeding one of them goes down, you can use the "Disable Failed Upstream" option in the "Extra Features" menu when managing your node. This option must be paired with a suitable "Custom Local Test Host" option. These two options should only be set on a gateway node.
"Custom Local Test Host" is the IP address which the gateway meshbox will ping to determine if its upstream is valid.
This IP address should be one which is past your local router, but not something on the public internet. If you foolishly set it to something like the IP address of a well known website on the internet then if that site is ever unreachable your gateway will think your entire internet link is down.
The best way to determine the ip address to use here is to login to your gateway meshbox and use the traceroute command to find an IP address which is past your router but still inside your ISP's network. Most likely these are routers and not something your ISP will change frequently.
For example:
traceroute -n ghzwireless.com
Then pick the first real ip address that appears on the route, eg not 192.168.x.x, not 10.x.x.x and not 172.x.x.x
Once you've picked the ip address to use as a test host, check you can ping it:
ping -n 80.10.20.30
(replace the example address 80.10.20.30 above with the ip address you've selected!)
If you get ping responses okay, then you can use this as the custom local test host.
If traceroute doesn't give you any output (eg there is a nasty firewall between you and the internet) then a choice of your ISP's nameservers or their customer website might be a good choice (as it is likely internal on their network), but beware that whatever IP address you are pinging, if that goes down then your meshbox will think your link has gone down.
Additionally, if you only have one gateway node, then there is no point utilizing this feature as all it will do is turn your gateway off if there is a problem with your internet connection.
Note that when a problem is detected, the gateway node becomes a repeater node. It needs to be powercycled/rebooted to return to its gateway function.
Also note that unplugging the ethernet cable will also result in the gateway node thinking the internet is down.
The disable failed upstream feature is available in build25dev86 onwards.