Greetings. I have the following question – I am setting up an old computer with OpenSuse for my 4.5-year-old son whose presence on Internet I would like to limit to few educational websites for kids. There are plenty of ways to do it under Windows, but I want my kid to start his computer experience with Linux… 
As I am new to Linux, I will appreciate detailed instructions. I basically need to block any internet access apart from several websites.
If you have a router with a configurable blocked sites/ keyword blocking section. This may help.
I’m not aware of any software for this. Maybe others are.
I’m not up on this, but Dansguardian will probably do what you want. I’ve just has a look for it via webpin:
Note: Search correct distro version for your system.
Hope this helps.
There is a couple of suggestions here, I believe you can replicate whitelisting with browser plugins, which has its faults.
Try the Firefox extension " Pro Con Latte "
Many thanks, ProCon is exactly what I meant. It does exactly what I need at this moment – blocks all but white list. Other feature are also good, but I don’t need them at this point. I know that it can be worked around with different browser, if kid is smart, but I will worry about it a bit later.
As far as router is concerned, it is probably possible to set up different access rules for different computers, (i have also mine and my wife’s) but I am not sure how to do it without studying the subject. (I have Linksys WTR54GL with original firmware).
What about Suse firewall? Doesn’t it allow for custom block all external connections but whitelisted websites?
I too have a wrt54gl with dd-wrt.
Its a must to have your firmware replaced and unleash its true power, and the level of configurating is insane.
Then its your all in one tool.
To flash my router with dd-wrt will be my next project… but right now I have a 7-week-old kid and plenty things to do… 
So I looking for simplier solutions…
great idea! than when he thinks of linux hell think of oppression and patricide.
lol!lol!lol!
Isn’t a 7-week-old kid too young to be on the Internet? Oh ok, it’s the other kid… 
Blocking a website is something usually done with a proxy and a URL/content filter like squid and squidguard or dansguardian. A firewall is too blunt a tool for this as firewalls don’t know about URLs only IP addresses so you have to enter all the possible IP addresses a site could use and that could be quite a few for sites that distribute their load across many IPs or use redirection, etc. Also you have to restart the firewall when you change the rules. So web filtering is normally done by an application, not in the kernel network stack.