I have an intermittent problem with my internet at home.

Every now and then, the connection to the outside world will grind to a halt. I can still log in to my router's html configuration page, and my router stil thinks the uplink to the internet is good, but I can't even get any dns, and my pings time out when I try to ping 8.8.8.8 (I haven't tried, but I suspect if I had a really long timeout, they might come back because the internet seems like it's still there but with close to zero bandwidth)

Anyway, I upgraded my wifi hardware recently, trying to solve the problem. I replaced both my Airport extreme wifi APs with Ubiquity networks Unifi APs, but nothing changed, I still get the same problem (which weirdly seems to be more common at night, particularly when it's close to midnight). So the Airport extreme APs were probably totally fine.

I also took my router out and replaced it with a really simple ADSL modem, but I get the same behaviour.

The weird part is, that when I disconnect my wifi APs from the router and connect directly to my router with an ethernet cable, my internet comes back instantly at full speed (I get a solid Sppedtest.net result every time). If I connect the wifi gear back up, sometimes it's ok for a while, and sometimes it quickly dies again.

It seems that one of the many wifi devices in the house is hammering the network somehow, but it's not practical to try and eliminate each one because the problem randomly goes away.

What I really need is some way to probe my network when the problem occurs and find out what's going on. A friend told me to download WireShark, which I did, but I wasn't sure what exactly to do with it.

Any advice on how to troubleshoot this?