Client can't connect to internet

[dankdragon]

Solution

As my collegue deHakkelaar pointed out. My firewall was blocking my requests. I though I added the ruls on iptables but it wasant, I just checked them out I were missing.

I would like to appreciate the time and effort to build, mantain and support for such a nice tool.

Expected Behaviour:

Run pihole as my dnserver.

Actual Behaviour:

Device raspberry pi 4 running ubuntu server raspberry distro.

Installed natively pihole and openvpn.

The first time when I setted the client with pihole as my primary dnsserver and other as a second. I saw how the pihole blocked some domains. But for some reason the pihole can resolve rest.

When I setup my pihole (192.168.1.4) as my unique dnserver the client can't resolve any domain giving me error of internet connection.

Currently I have my company router that does as the DHCP server (192.168.1.1). A second router (192.168.1.2) wired to the company router that extends the wifi network of my house. Is configured in the same range of ip.

I noticed that in the debug log the pihole can't discovery any dhcp server. I can't figure out why either how to fix it.

nmap info

$ sudo nmap --script broadcast-dhcp-discover -e eth0
Starting Nmap 7.80 ( https://nmap.org ) at 2022-10-31 19:56 CET
Pre-scan script results:
| broadcast-dhcp-discover:
|   Response 1 of 1:
|     IP Offered: 192.168.1.71
|     DHCP Message Type: DHCPOFFER
|     Server Identifier: 192.168.1.1
|     IP Address Lease Time: 2m00s
|     Renewal Time Value: 1m00s
|     Rebinding Time Value: 1m45s
|     Subnet Mask: 255.255.254.0
|     Broadcast Address: 192.168.1.255
|     Domain Name: home
|     Domain Name Server: 192.168.1.1
|     Router: 192.168.1.1
|_    WPAD:
WARNING: No targets were specified, so 0 hosts scanned.
Nmap done: 0 IP addresses (0 hosts up) scanned in 3.97 second

Debug Token:

https://tricorder.pi-hole.net/ySPy6Nxk/

[deHakkelaar]

@dankdragon

| Server Identifier: 192.168.1.1

Above line says a host with IP 192.168.1.1 is acting as a DHCP server for your LAN segment.

@dankdragon

| Domain Name Server: 192.168.1.1

Above says its handing out its own IP 192.168.1.1 to the clients to be used for resolving DNS.

Preferred is below (also check the links inside):

https://docs.pi-hole.net/main/post-install/

And about clients having Pi-hole + another for DNS:

Why should Pi-hole be my only DNS server?

Reduced Ad Blocking Capability The main reason you should Pi-hole as your only DNS server is that you will see increased performance in the blocking of ads. If you have two DNS servers (Pi-hole and something else), your network clients may not always query Pi-hole for name resolution. If a query happens to be answered from a non-Pi-hole DNS server, your block lists will not apply (since that DNS server doesn't know about them). All Queries Need To Go Through Pi-hole First Since other DNS se…

Sounds like a firewall issue on either the host itself or some router safety mechanism blocking:

Prerequisites - Pi-hole documentation

Why won't Pi-hole work with DNS rebind protection enabled?

What is DNS rebind protection? If your router has an option called DNS rebind protection enabled, you may run into issues when trying to use Pi-hole as your DNS server. The reasons for this are quite technical, but to summarize what this option does in one sentence: DNS rebind protection does not allow DNS queries to be answered with a local IP address. Why does this interfere with Pi-hole? DNS rebind is meant to be a countermeasure to an attack on your network. So in many cases, it's ac…

[dankdragon]

First of all thanky you for your time.

I would like to clarify that I have setted up two dns servers because pihole is not working so I remove and put back the second dnsserver to have acces to internet meanwhile.

I will deffinetly check that DNS rebind protection.

I will update with more info with wathever I find.