Pi-hole is blocking ALL internet access after a fresh install (SOLVED: not Pi-hole related)

[Tikay]

Expected Behaviour:

Pi-hole only blocking stuff in the blacklists.

Actual Behaviour:

Pi-hole blocks internet access completely.

Debug Token:

https://tricorder.pi-hole.net/8oyhxsndvu

What I did on a new RaspBerry Pi 3 B+ (specifically bought for Pi-hole):

• Installed 2020-02-13-raspbian-buster.img on a 8GB Micro SD card, including the last updates.
• In the router (TP-Link Archer C9) set DHCP to give the RPI a static IP address: 192.168.0.250 (Ethernet connection).
• Installed Pi-hole using: curl -sSL https://install.pi-hole.net | bash
• Enabled the web interface (works).
• Set up remote access to the Pi by installing tightvnc and xrdp (am using mstsc.exe from Windows to access the Pi).
• Turned the RPI off and on (can connect to it using the Pi-hole web interface, and mstsc.exe).

On the router: under DHCP config, I set the DNS server to 192.168.0.250

To test: disabled/enabled WiFi on my phone. It gets the correct DNS server IP: 192.168.0.250
Result/problem: NO internet access whatsoever (websites, apps) from my phone.

Things I've tried:

• Using different DNS servers (Google, OpenDNS, others).
• Disabling all six entries in the Blacklists.
• Disabled WiFi (and Bluetooth) on the RPI.
• The RPI can connect to internet just fine, open websites etc..
• ran: pihole -r ("Reconfigure or Repair Pi-hole subsystems").
• Search for solutions for hours, to no avail. Similar problems seems to have different, unrelated causes.

I'm barely familiar with RPI/Raspbian etc.
What can I do to find the source of this problem?

[jfb]

Your Pi-hole debug log is normal and shows that Pi-hole is working properly. That puts the problem elsewhere on the network.

What is the make/model and OS of your phone?

Do you have another client that you have tested with - laptop, desktop, etc. It appears you do since you are running a Windows machine.

From the Windows client command prompt, what is the output of nslookup pi.hole

[Tikay]

Thanks for your swift reply. In the router I just set the first DNS entry to the RPI (192.168.0.250) and the second DNS to 192.168.0.251 (that's not in use, yet I can't enter 0.0.0.0).
Then on windows renewed the lease: ipconfig /renew

ipconfig /all
Default Gateway . . . . . . . . . : 192.168.0.1
DHCP Server . . . . . . . . . . . : 192.168.0.1
DNS Servers . . . . . . . . . . . : 192.168.0.250
                                    192.168.0.251

On the Windows PC (ethernet connection) I DO have internet access. Didn't test that earlier (figured that if one doesn't work, no device will)...

On an iPad (with mobile data disabled) I get the correct DNS servers and DO have internet access...
The phone is an iPhone Xs. I've tried setting Mobile Data off, doesn't make a difference.

nslookup pi.hole
Server:   raspberrypi
Address:  192.168.0.250
Name:     pi.hole
Address:  192.168.0.250

On the PC, in the browser pi.hole goes to the web interface.
On the iPhone AND iPad, pi.hole doesn't work ('can't load page').
Tried with a second iPhone (model 7): same result as the Xs, doesn't work.
Also tried a second iPad: same results as the first iPad, DOES work. So only the iPhones are not working for some reason....

[jfb]

@Tikay

On the iPhone AND iPad, pi.hole doesn’t work (‘can’t load page’).

The full URL for the admin GUI page is http://pi.hole/admin

An alternate is to use the IP - in your case http://192.168.0.250/admin

Do either of these work from the iPad or iPhones?

[Tikay]

On the iPad both those URLs DO work.
On the iPhone they both do NOT work.

Ahhh I know what the issue is; the iPad is connected to a WiFi that can see the local network.
The iPhones are connected to a guest network, that can ONLY go to the public internet....

All four devices can connect to both the 'local' WiFi and Guest WiFi, and as luck would have it both iPads were connected to the 'local' WiFi, the iPhones were both connected to the guest network...

Just tested this: connected an iPhone to the internal WiFi, it works now. Thanks a lot for your help.