I hope the title isn't to unclear but let me go a little further. I need to content filter the web on this linux machine (just this one not a whole network) I don't need anything too reliable mostly just trying to block common keywords related to porn and drugs and stuff. I want to use iptables and I'm with that all the way mostly because I'm not using 3rd party programs (really meaning programs that didn't come with the OS when i say that) i need to match by keyword please. Also is there a way to direct them to a webpage at the localhost page? cause if so I'd like to know how to do that too please. I've done plenty of research on this but I'm a little concerned of what happens if i do it wrong how reversable is it and it might be tough if I use just anyones example

iptables was not built for content filtering, hence it would not be the best tool here. HTTPS traffic would be completely invisible for iptables.

You could use string matching of iptables for the keywords you want to block but instead of dropping or rejecting the packets, just redirect them to your localhost. You could set up a static error page on your localhost on say port 8080 and redirect to localhost:8080

A transparent squid proxy would fit your requirements better.

I know that squid be better but again like I said I'm set on iptables and thats because I know what you told me about HTTPS I understand that and I'm not concerned about that at all one bit I'm not asking for some intense content filtering. I just need to get the majority of traffic used on a normal basis covered is all everything else will be kept track off in other ways that I'm not too concerned about. Now could I get an example though of what I'm asking everything on the internet is evertyhing BUT string matching iptables for the keywords. SO please lets try and stick away from squid and stuff because I also can't even figure out how to set that up properly so also unless you have somewhere I can get a complete guide for what I NEED then please try to refrane from it