|If the connection isn't active you can't test it.|
You would logon to each dual wan port router [assuming that is what you are using] and note the wan ip and gateway ip being used. But again those won't help you test.
Best you can do is download the router logs and review them. No "dropped connections" means the link would be up. If cisco routers [not linksys] you can do a show interfaces which will list each interface and its uptime.
Usually the wan ports on routers are set to not return icmp [ping and tracert] as a way of not being seen by hackers. You could enable icmp return and then from a remote site ping all of these remote wan ips with a ping -t sent to a log. You would end up spending a lot of time reviewing these logs.
BTW you would never use the gateway ip of the lan to test.
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