Thank you both for responses. Of course I Googled this question before I put up my post, however,.specific Second Life settings are not covered by any of the standard web pages on this. Thats why I was specifically addressing my question to Second Life users who use Smoothwall. For info to Rolig, Smoothwall is a UK company, not the Philippines, that sells a corporate firewall but also a free version for single users which is what I'm using.
Thanks anyway.