TCP traffic works fine from end to end, but some traffic especially HTTPS with large certification file get timeout

Products

• VMware NSX

Issue/Introduction

• Some TCP traffic (even SSH) works fine from end to end,
• Some traffic especially HTTPS with large certification file get hung/timeout 
• We see the browser keeps spinning without getting the web page Loaded

Environment

VMware NSX 

Cause

VTEP MTU is not 100 bytes more than the end point VMs, then, packet with large certification would be close to 1500, by adding geneve overheader (68 bytes), the packet size on the VTEP side would be lager than 1500 which is default MTU for lots of physical switches and routers

Resolution

Configure MTU to 100+ more than VM MTU