Downloading a Symantec Endpoint Protection (SEP) unmanaged client requires access to the Broadcom Support Portal using a valid license or serial number
Sylink.xml: As noted, this file is the handshake. In an unmanaged client, this file is either absent or contains XML tags that point to liveupdate.symantecliveupdate.com rather than an internal IP.Cmano.config: This file controls the Communication Manager settings. In an unmanaged scenario, this is configured to allow direct internet access for definition downloads without tunneling through a management server.This is an advanced Broadcom utility often used by support staff. Sylink
An unmanaged client of Symantec Endpoint Protection (SEP) is a standalone installation that does not report to a central management server (SEPM). Instead, it communicates directly with Symantec LiveUpdate servers to download virus definitions. Broadcom TechDocs Key Performance Review Reviewers from platforms like Sylink.xml : As noted
Look for files named: Symantec_Endpoint_Protection_[version]_All_Clients_EN.zip . Sylink