TCP-IP suite and Firewalls

[jle @ ost . fr (Jean-Marc LAFAYE)]

Hi All,

I'm new to this list and I'm interested about firewalls and security issues
because our company -recently attached to the internet- wishes to offer 
internet's services to many people, without damages for our integrity.
So, I have to plan the interconnection between a registered network -used to 
access to the internet- and an unregistered one -used for internal purposes, 
such as text processing or spreadsheet-.

Reading various articles, it seems that firewalls and TIS-toolkit are designed
for full-IP networks. Is it right ?

If internal network is not based on TCP/IP suite, does an appropriate gateway 
insure a good protection ?

At least, what type of data could I leave on the machine directly attached to
internet ? Is there any risk with NIS or DNS data bases ?



Thanks for any help you me be able to provide.


PS : Appologize for my scholar english :-).