Can anyone help me? Tableaut/Forticlient 4.02300/ Verizon FiOS?

Long story short:

My Dell laptop running Windows 10 will not allow a Tableau software connection through my company VPN when connected to FiOS router. My same laptop can connect to my company VPN if I use my Verizon 4G wireless access point.

This worked as recently as a few weeks ago. My IT department is pointing me to Verizon. Verizon spent a few hours with router settings, to no avail.

I’d appreciate any leads you can throw. I consider myself dangerous with regard to my network chops.

I will say this: FortiClient appears to connect and work, but I cannot Tableau to talk. If I change to 4G connection, it works.

Any help is appreciated. Thanks.

Hi there. So it sounds like you have two categories of connectivity:

  1. FiOS + Forticlient VPN (which worked until a few weeks ago)
  2. Verizon 4G + Forticlient VPN (which still works)

You mention the Tableau software doesn’t work with #1; does anything else work? Under #1 can you ping a host on your company’s private network? Can you ping an internet host?

One possibility is a Path MTU discovery issue (PMTUD). If a router on the FiOS connection is filtering ICMP (due to some configuration change) this can break discovery. IPsec negotiation doesn’t typically fill a given packet to your MTU but transferring data with other applications can, resulting in what you would perceive as a successful VPN connection that won’t do anything (but still increments packet counters).

Under condition #1, verify with your fortigate administrator that they see an actual “tunnel up” event when you VPN and that the connection stays up on both sides for a while (removing the possibility of a tunnel-up followed shortly thereafter by a tunnel-down).

edit: I should mention that I made an assumption you’re using an IPsec VPN vs. a tunneling SSL VPN with your forticlient. For tough-to-solve VPN problems and on rare occasion I’ve used a tunneling SSL VPN with some people and it got around their issues. I always prefer to know the real cause of a problem but time and circumstance can work against us.