[TriLUG] Linux Host connectivity issue

[Matt Flyer via TriLUG]

I am experiencing a strange network issue and I am not sure how to go
about diagnosing the cause.  I have a Linux box running Ubuntu 16.04.
 It is in a vlan with with a gateway IP address.  The network is wired
and the wireless interfaces are disconnected.  The ethernet line comes
into a local switch on my desk and from there to the PC.  

Intermittently I am losing (Internet) connectivity and when this
happens I can't ping the gateway but I can, at least almost always,
successfully ping other hosts in the vlan. I tried removing this
switch and plugging directly into the wall jack.  No difference.

My initial thought was that there is a problem with the main switch or
router, which I don't have access to, but here is where it gets
interesting.  Nobody else is experiencing trouble, nor am I seeing the
problem if I boot the PC up in Windows instead of Linux.  Also, while I
am unable to ping the gateway with this machine, I can ping it with
another (windows) machine plugged into the same local switch on my
desk.

In other words, it appears to be an issue with the software (?) on this
PC, but I don't know what or why.

Any suggestions?