WAN performance - sudden change

[jasonwood]

I have two remote locations that connect to FileMaker over the WAN. This has been working relatively well for years.

For the last 3 days we have been having major problems. I can see the remote users in the Connected Clients list briefly, but they just get the spinning beach ball of death.

On the weekend, I used speedtest.net to determine that my server's connection was running seriously slow, but today I've been getting reasonably good numbers and it's still not been working. Until now, that is... now it's working just fine. But I'm worried this is going to happen again tomorrow or another day...

What kind of diagnostics can I do to figure out if my ISP might be doing something to FileMaker traffic? What else can I look at?

Using Server 11.0.3.309 (latest version)

[Steven H. Blackwell]

When was the last time you restarted your server? Also, check your cables and network cards and switches. Something may be starting to fail here.

Steven

[jasonwood]

I was installing updates and restarting the server and router throughout the weekend and it didn't seem to make any difference.

I continued to have problems after my post. Then I setup an L2TP VPN 2 days ago and noticed an immediate and significant improvement in performance since using the VPN.

That's the opposite of what I expect since the traffic has to go through an extra computer (my VPN server).

Does that mean my ISP is interfering with FileMaker traffic or is there some technical reason why it would perform better over a VPN?