You want to know what ports are needed to be open in the firewall/proxy in order for anti-virus definitions and premium anti-spam rulesets to download.
Below are the requirements
If Premium AntiSpam will be used additionally it is needed
There are workarounds offered by Symantec in order to bypass the above requirements going through a proxy. However these workarounds are only provided "as is" since they are depended on the Operating Systems System accounts capability and restrictions to download which can not be troubleshot by Symantec as it is outside the support boundaries.
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