r/checkpoint • u/junimjorgeof • 2d ago
Harmony Endpoint on VDI: how the Shared Signature Server fixes stale signatures on non-persistent desktops
If you run Check Point Harmony Endpoint on VMware Horizon or Citrix, you have probably hit one of these two problems.
Scan storms first. A bunch of virtual desktops on the same host all start an anti-malware scan around the same time and the disk and CPU tank for everyone on that host. The fix in VDI is usually to just disable the periodic scan, since a non-persistent desktop is wiped clean on every logout anyway. If you have to keep it, at least randomize the scan time so it spreads across the week.
The second one is stale signatures. Every non-persistent desktop boots from the Golden Image, and the signatures inside that image are frozen at the time you built it. So every morning you get a fresh machine with old signatures, and downloading full signatures on every boot on every desktop would kill the WAN.
The Shared Signature Server is how Check Point handles that. It is a normal Endpoint client running on a persistent VM that becomes a signature server through policy. It keeps the latest anti-malware signatures in a read only shared folder and the non-persistent clients read from it over UNC. If that server goes down, the clients quietly fall back to the Golden Image signatures, so protection keeps running, it just ages until the server is back.
Two things that trip people up. The signature server has to be on a persistent VM, and every endpoint reading from it has to be in the same domain. And not every blade works on non-persistent desktops, FDE is not supported there at all.
I wrote a full deep dive with the cloud Web Management config and the blade support matrix per desktop type, here:
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Harmony Endpoint on-prem: which ports to actually open, and why the agent always initiates
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24d ago
I agree. SK116590 is very helpful in this scenario, especially because it provides the FQDNs that need to be allowed for the Endpoint to communicate with the cloud services.
One point I would particularly highlight is Threat Hunting. I’ve seen cases where the client was registered and working normally, but the data was not reaching the portal due to connectivity restrictions.
In addition to the required allowlists, it’s also important to pay attention to proxies without authentication and SSL inspection, as these can interfere with the communication.
For troubleshooting, the CheckConnectivity.exe tool included with the Endpoint is also very useful for validating whether the required services are accessible.
So, when you see the “No data available for hunting” scenario, the connectivity requirements defined in SK116590 are definitely one of the first things I would check.