SonicWall: Configure a Firewall (TZ series) to Permit WSUS Downloads
Occasionally, SonicWall firewalls will block WSUS downloads. You can correct this by accessing a "hidden" page in the SonicWall interface, as follows:
1.Logon to the SonicWall interface.
2.Change the file name at the end of the URL to diag.html.
3.Check the "Enable HTTP Byte-Range requests with Gateway AV" checkbox.
4.Click the Apply button to save changes.
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