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Zscaler NSS Source Connection Breaks When TLS Is Enabled

  • Feb 25, 2026 4:25 PM UTC
  • 30 replies
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mmarker
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Hey all - Working on configuring our Zscaler Cloud NSS feeds to send over to our cribl.cloud worker groups. Using the zscaler_nss Source but when i enable TLS - the connection breaks (not understanding why). Just need a sanity check that my configuration is proper. The cert is something we established for this use. Maybe something is off on my zscaler side?

Best answer by Jon Rust

Try connecting with curl or openssl to test the certs
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30 replies

Jon Rust
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  • Feb 25, 2026 4:25 PM UTC
Try connecting with curl or openssl to test the certs

mmarker
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  • Feb 25, 2026 4:26 PM UTC
From what endpoint exactly? Seeing as this is Cloud NSS Feeds flowing to Cribl.Cloud?

Jon Rust
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  • Feb 25, 2026 4:26 PM UTC
endpoint doesn't matter for this test. We just want to validate you have TLS set-up properly

Jon Rust
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  • Feb 25, 2026 4:26 PM UTC
host and port is all that's required

mmarker
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  • Feb 25, 2026 4:26 PM UTC
Can you throw me an example of the curl needed?

Jon Rust
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  • Feb 25, 2026 4:26 PM UTC
curl:
curl -v https://ingest-address:port
openssl
echo "" | openssl s_client -connect ingest-address:port

mmarker
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  • Feb 25, 2026 4:26 PM UTC


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Jon Rust
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  • Feb 25, 2026 4:26 PM UTC
8088 is by default assigned to hec source

Jon Rust
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  • Feb 25, 2026 4:26 PM UTC
did you disable that source?

Jon Rust
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  • Feb 25, 2026 4:26 PM UTC
In Cribl Cloud, Products -> Workspace -> Data Sources shows which ports are assigned to which sources You can reuse ports, but you need to make sure the originals are turned off

mmarker
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  • Feb 25, 2026 4:26 PM UTC
Yeah within the Data sources there isnt anything focused specific to the Zscaler NSS Hec source

Jon Rust
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  • Feb 25, 2026 4:26 PM UTC
yes, expected

mmarker
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  • Feb 25, 2026 4:26 PM UTC
This is also the port dictated to use directly from the Zscaler Documentation when deploying a Source in Cribl

Jon Rust
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  • Feb 25, 2026 4:26 PM UTC
you need to define the source and choose an AVAILABLE port to listen on

mmarker
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  • Feb 25, 2026 4:26 PM UTC
ok but even when i go to enable TLS and change it all over to 443 - it still wont work

Jon Rust
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  • Feb 25, 2026 4:26 PM UTC
8088 isn't available out of the box. In order to use 8088, you need to disable the existing source that is already using it -- Splunk HEC

Jon Rust
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  • Feb 25, 2026 4:26 PM UTC
you can't use 443

mmarker
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  • Feb 25, 2026 4:26 PM UTC
which it is disabled

mmarker
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  • Feb 25, 2026 4:26 PM UTC


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Jon Rust
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  • Feb 25, 2026 4:26 PM UTC
Choices:
  • use one of the ports that is assigned to a default, but DISABLE the default first
  • use a port in the range 20000 - 20010

Jon Rust
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  • Feb 25, 2026 4:26 PM UTC
you have that set to 10080?

mmarker
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  • Feb 25, 2026 4:26 PM UTC
Thats our ZIA Alerts Source (Which currently works fine)

mmarker
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  • Feb 25, 2026 4:26 PM UTC
Right now im working through the Zscaler NSS Source

Jon Rust
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  • Feb 25, 2026 4:26 PM UTC
after adding the zscaler (pic), did you commit and deploy?

mmarker
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  • Feb 25, 2026 4:26 PM UTC
So basically you're saying that I can use port 20001 for instance. Configure that on the Z NSS Cloud Feeds making sure it's https and it should work?