When I converted the router at the school I support, I configured Diversion to use the Medium block list. I then got complaints that FB was blocked as well as messenger. I changed to Standard.
I have seen the problem you describe. It can be a challenge trying to find the offending domain. FB may be using CDN for images which makes it even more challenging to identify. If you need a short term fix, change to Standard to keep users on your network happy!
You can see the facebook entries in the blocklist file using this command.
Code:
grep "facebook" /opt/share/diversion/list/blockinglist
Here are a list of FB domains I got via a web search:
Code:
27.0.0.1 www.facebook.com
127.0.0.1 facebook.com
127.0.0.1 login.facebook.com
127.0.0.1 www.login.facebook.com
127.0.0.1 fbcdn.net
127.0.0.1 www.fbcdn.net
127.0.0.1 fbcdn.com
127.0.0.1 www.fbcdn.com
127.0.0.1 static.ak.fbcdn.net
127.0.0.1 static.ak.connect.facebook.com
127.0.0.1 connect.facebook.net
127.0.0.1 www.connect.facebook.net
127.0.0.1 apps.facebook.com