I'm happily running pi-hole on my lan but what if I'm elsewhere (outside my LAN)? Is there a way to use my pi-hole setup?
Also, if I wanted a friend to access my pi-hole as a test to see the functionality and benefits, is there a way that I could direct external DNS requests to my pi-hole? BTW: the friend is using a Peewee at work and I think they can change their DNS settings.
How do I verify that I didn’t setup an open resolver? Also, why would it be a bad idea to have a DNS server like the pihole on the internet accessible by all?
An open port 53 on the internet is quickly discovered by port scanners and will soon be put to use for nefarious purposes.
You can check your network for open ports at that link or at one of many websites. I generally use Shields Up. First page click "proceed" and on the subsequent page select "all service ports" and it will check your first 1056 ports. This will include port 53 (DNS). The resulting matrix should be green.
No. They have sophisticated controls to prevent attacks through their resolvers. So, while accessible, they aren’t considered open resolvers. An open Pi-Hole has no defenses and is an open resolver.