Need help with building a gateway (OPi PC 2, Armbian, PiHole etc)

[bozden]

Hi friends, I've been away from SBC's (and you) for two years. With covid-19 at hand and all family at home remote working/learning, I wanted to redesign my home-office network. I bought two managed switches (Zyxel 1200GS-8) in order to introduce VLANs, transformed the office server to a router etc. I try to build a SBC gateway between public and home network but got myself into trouble. I'm working on this for three days now but couldn't get it working. I messed around a lot and got lost, need second (and more) eyes to debug it.

 

Here is the network layout: 

About the gateway:

• OPi PC 2 ( has 1Gbps port connected to home NW) augmented with a 100 Mbps USB Ethernet (to router)
• Latest (as of 2020/10) Armbian (Ubuntu 20.04.x based)
• I removed Network Manager and switched to systemd & netplan (all my installations have these and they are very intuitive - and got stable)
• Installed PiHole (manually from command line, disabling OS check) to serve .64.* home network.
• Enabled ufw and handling the port/interface/subnet routing with before.rules

 

What is working:

• Can ping/traceroute/dig from the gateway
• Can ping/traceroute/dig from the server
• PiHole up and running as DNS and DHCP, home network devices can get IP from the PiHole DHCP server

 

Problem: No internet connection on devices getting IP from PiHole DHCP

 

I saw many such posts with PiHole but each problem is unique - and PiHole is new to me. What I understand is it is not working like industry standart SW like Bind9 & ISC-DHCP. There are many many stuff in play and I've got lost.

 

(I played too much with the config files so I don't want to post them beforehand.)

 

How can I debug this? There must be something I'm missing...

 

Thanks in advance...

Bülent Özden

 

[bozden]

I feel so dumb !

 

After many hours of tcpdump'ing and log tailing I found my mistake... Just to record this unfortunate event:

I first installed pihole DHCP for the exterior network (192.168.100.0/24) then moved to home-network (192.168.64.0/24) side.

On the web interface there is a "Router (gateway) IP address" and my router is in at 192.168.100.2 - I left it as it is  That should be on the same subnet of course  Changed it  and it worked...

 

Sorry for your time