High utilization caused by decryption

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High utilization caused by decryption

L2 Linker

I dunno if anybody else has run across this or not but I just felt compared to share.  I have been having fairly continious performance problems with a 5050 cluster and last night I isolated at least one culprit that's been adding to that problem.  We are in the process of rolling out Windows 10 and a bunch of new Microsoft apps AND our firewalls decrypt the vast majority of our outbound traffic.  As of late I've been getting all kinds of complaints about browsing the web, pages can't be displayed or it takes multiple refreshes to get content to appear and the list goes on and on.  After staring at the raw traffic logs for hours and after generating a couple of reports to show my top accessed web sites, traffic going to watson.telemetry.microsoft.com was the top site by several orders of magnatitude. Over the course of 24 hours, I had several thousand machines hitting that site to the tune of a half a million times.  My top 25 "hit" parade had traffic to that site alone actually being more than the rest of the 25 combined.  All of it was being decrypted.  When I threw that fqdn into a bypass group the utilization dropped by almost 45% initially.  Now I'm seeing closer percentages of just over half.

I used to see substaned cpu utilization averaging between 60 and 70% with gusts to 100, now everything is around 35% with the occasional peak in the low 70's.  Learn from my fail.


Thanks a LOT Microsoft!


L7 Applicator

Hi @bwsaloum 

It depends on the number of clients your PA5050 has to protect. So depending on this number it is not only the fault of Microsoft (while it still is for a major part). The PA5050 is no longer strong enough to decrypt a lot of connections with modern encryption algorithms. From what you describe your PA5050 seems to be still enough for your clients. Anyway we had the same issue, where the hardware was strong enough for years now this is no longer the case. So my conclusion is the PA5000 series is end of sale for a good reason. This hardware is still good for almost everything but not really for decrypting TLS connections ...


the 5000 series are just barely covering things as it is but we have plans migrate to 5200 series devices sometime in q4 (I hope)


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