All ports listed here have to be opened in the firewall’s rule set. As most Windows firewalls are application based you can save yourself some trouble by adding a rule which allows the eMule.exe all UPD,TCP traffic on all ports in all directions. This will not compromise your security, as no exploits of eMule are known so far.

Notes:
- ZoneAlarm is reported to cause problems with eMule. It is not recommended. Nice and free firewalls are Kerio Personal Firewall and Agnitum Outpost

- I'll add some more configuration examples as time allows. If you want to contribute then write a nice guide on how to use your favoured firewall. Add a few nice screenshots and send it to Monk@emule-project.net