We've found a very strange issue with our Verizon 4620LE MiFi's running firmware version 3.30.13. Around late December they no longer allow Network Connect to function correctly. We're seeing severe packet loss. Most DNS lookups fail. Persistent pings work for a while and then start failing. Web pages fail to load or only partially load.
Verizon suspects an MTU issue but is pretty much stumped. I'm curious if anyone else has experienced an issues like this.
Have you tried turning off "VPN Passthrough" on the mifi device?
Thanks for the suggestion. I tested with VPN passthrough enabled and then with it disabled. It doesn't make a difference.
I did notice that the issue only seems to affect Network Connect traffic. Traffic handled by the rewriter or the Juniper RDP client are unaffected and work fine as long as Network Connect isn't running.
Verizon was under the impression that this is an MTU issue, but they can't explain why it only affects one particular firmware on one particular device. They're now focused on getting a new firmware from Novatel, who makes the MiFi's with the issue.