u/Dalalee4

TCP Quick ACK (more) questions

Hello! As i was doing research for SMB/DFS slowness issues on ZPA, i came across some previous posts discussing TCP Quick ACK ([1], [2]).
I am in a similar situation, where i have tried just about every recommendation from Zscaler and Reddit: dedicated App Connectors for SMB, TCP Quick ACK enabled on the App Connector Group, SMB 2 vs 3, Private Service Edge, various ZCC versions; no joy.
I raised a support case with Zscaler and i was told that they can enable TCP Quick ACK in the backend, typically kept as an optimization enabled only when needed.
The way it was presented to me, this is a tenant-level setting, which will apply broadly to all ZPA TCP traffic.
I was encouraged that there should not be any noticeable issues, other than a slight increase in ACK traffic that could potentially lead to a increased CPU/memory/network consumption.

As this is a global setting, i was wondering if anyone in the community has it enabled in their tenant and noticed any improvements from enabling it, or has faced any issues after enabling it.
Thank you!

reddit.com
u/Dalalee4 — 2 days ago