Permanent Ban System From Website ? Just Confused!

Hello mates,
I just want to know about how we can ban someone permanently to enter the website? I want to stop some users to even view my websites. For sure, banning ip is not a solution as now a days even a kid know about changing an ip. Some people say Ban Mac Address .. But, that is also not easily possible.

Many of you know about Hack Forums/Dot/NET .. once you are banned from your IP .. you can never join them back even from vpn, socks etc or anything else :/ This is the message comes
[403 Forbidden Error] - You might be blocked by your IP, Country, or ISP. We also block VPN's, proxies, datacenters and socks.

I want a system like that.. can anyone help me out to know more on this?

Why would you want to ban an entire nation or ISP?

Well, basically I have a Chat Room website among my other websites. I have tried many chat room software but I am unable to ban spammers permanently. IP Ban is useless these days. And so, I am expecting a solution like hack forums.
And yes, I do not want to Ban a whole nation. But a user only!

sudo echo ALL:ALL /etc/hosts.deny will lock out everyone from accessing your server except for those defined in /etc/hosts.allow. Look up the offender's hostname and you can deny by hostname too, like: somefag.fagisp.net or ip 1.2.3.4 http://its.virginia.edu/unixsys/sec/hosts.html you can also deny them in ip ranges in .htaccess files like http://stackoverflow.com/questions/4400154/htaccess-deny-all-allow-only-one-ip order deny,allow deny from 1.2.3.0/24 //bans an ip range from 1.2.3.0 to 1.2.3.255 /24 means an ip range of 256 ips, /23 is a range of 512 ips eg 1.2.3.0 to 1.2.4.255, /25 is a range of 128 ips 1.2.3.0 to 1.2.3.127 and so on allow from all. if somehow your analytics had access to his MAC address, you could ban that too. Don't know if using proxies gets around that. or use manual registration approval.