VMWare Network Hickups ( sent link down event. )

I ran into this because I went to a hotel that had DHCP renew every 300 seconds, trying to download something inside the VM was getting clobbered...

If you check your syslog or kern.log and see the following entries; then I might have the solution for you:

kernel: [235397.022939] userif-3: sent link down event.
kernel: [235397.022943] userif-3: sent link up event.

Then the issue is one that when your DHCP renews it calls into the kernel with the new information; unfortunately this causes VMWare Workstation & Player (might effect other VMWare products?) to reset its network stack, even though nothing changed...

The solution after a lot of time googling different terms and trying to figure out what exactly was going on. I finally found it here (by Jan Just Keijer): https://www.nikhef.nl/~janjust/vmnet/ it was for an much older version of VMWare Player; but the solution still applies to VMWare workstation 15...

To make sure the information doesn't just disappear in the future (and so I can easily find it myself) I'm going to quote the relevant code and/or modifications I did..

Extract the /usr/lib/vmware/modules/source/vmnet-only.tar tar file, you need to modify the userif.c file. Search it for VNetUserIfSetUplinkState function and right after the variable declaration add if (!linkUp) return 0;

// Around line 966
VNetUserIfSetUplinkState(VNetPort *port, uint8 linkUp)
 {
    VNetUserIF *userIf;
    VNetJack *hubJack;
    VNet_LinkStateEvent event;
    int retval;

    /* ADD: never send link down events */   
    if (!linkUp) return 0;
    /* END Added code */
    
    ... rest of code ...

This will eliminate the linkdown events; which disconnect the internet from the VMWare network driver...

After you do that; recreate the vmnet-only.tar and replace the original. Then you can run: /usr/bin/vmware-modconfig --console --install-all

And then either
systemctl restart vmware
or
service vmware restart

If you still see " sent link down event." in your logs; then the patch wasn't applied properly.