You might want to add to bitcoin.conf:
listen=1
server=1
Discussion
Thanks, both were already set. Do you need the Initial Sync to be done before 8333 opens?
No, you should be able to connect to it right away. The daemon will know if the initial sync is complete or not and report that accordingly. If you connecting from a different machine you'll need to open up access so rather than 127.0.0.1 you'll need to bind to the ethernet adapter or you could use 0.0.0.0 for all
Also, after making changes to the config, you need to restart bitcoind or bitcoin-qt whichever you're running to re-read to new config