Connections To/From Guests Fail After a Few Packets

[jamoiholland-uk]

Strange issue. New ESXi 7.0U2 install on NUC8i5BEH, with the additional drivers for the onboard LAN and USB NIC. Onboard LAN NIC is mgmt of ESXi only, USB NIC is multi-VLAN (dot1Q) and all guest are connecting over this physical NIC.

I can connect to a guestVM using ping/SSH/HTTPS from a WindowsVM guest on the same ESXi host, both in the same subnet. When I connect to the same guestVM from outside the ESXi host, in the same subnet again, I can ping, but when I SSH it hangs after entering the username and password, and HTTPS hangs after ServerHello.

I'm trying to work out why, from outside the ESXi host, there is generally good connectivity up to L4 but for some reason as TCP conversations progress, things break.

I'm also experiencing the same in the opposite direction, where guest VMs can ping outbound to the local subnet and beyond to the Internet, but general Internet browsing over HTTPS is failing.

Thanks 🙂

[jamoiholland-uk]

Right, getting closer to narrowing this down. The guest VMs work fine when I move them to use the NUC's onboard NIC, the strange behaviour is only present when using the USB NIC. Driver problem?

[jamoiholland-uk · Accepted solution]

FYI, for anyone else seeing this in the future; I replaced the USB NIC adaptor with a Startech USB3.0 1GbE adaptor, re-built a new ISO on 7.0u1 with the community USB drivers (https://flings.vmware.com/usb-network-native-driver-for-esxi) and all was fine. It was either the old USB NIC adaptor, or driver issue, or 7.0U2, or maybe more than one of those in aggregate that caused the issue.