On an as empty as possible Windows 10 machine I noticed
For ZClient TCP 11667, 5080, 5443, 6119, 8216, 9005-9006, 10222, 23300, 23310, 23390, 23395, 23760, 23840, 33900, 33910, 34900-34901, 34920, 47100, 47127, 48377, 48480-48482, 48486 and UDP 32900-32901, 34910.
But there is an other range from at least TCP 50293-50357.
This range is larger, but I don't want to give your server too much trouble. This is the last range of TCP I need to know for ZClient. ZServer I cannot discover yet I have to play at least one full day game time :-( by ZClient.