First things first. There is no 100% filter. You should have seen the stuff I got while trying to research slavery in America. Well maybe not see… Anyway, there are always going to be images that get by and what some consider inappropriate others call culture or art so… Good Luck.
OpenDNS has been around for years. I use it at the school for the quick no thinking behind it. After setting up an account, you just add their DNS address to your server or firewall and… Done. (Sort of…)
You can see here you have lots of categories to choose from. I found using the built in Low, Moderate or High, caused a lot of stuff through or simply not enough.
So, I go for Custom, pick your poisons and extras if you want. Be aware that some sites fall in to multiple categories and you can end up blocking something very tame because there’s an option to share or comment on the site.
EAt the very bottom you can add specifics. We don’t mind the students having a Facebook account we just don’t want them on it all day, (like their parents). Instagram is a no brainier.
Again, this is only while at school, once home or Starbucks, it’s wide open.
OpenDNS offers a new service called Umbrella. (Ella Ella Ella, if you get this reference. Your still cool.) It was way too expensive for us but maybe you are better than us… Ladeedaa.
So, with OpenDNS and our Meraki firewall (which will be another post), I have pretty good results for content filtering at school.
If you have any other suggestions. Please, comment.