A static IP has been configured on my Linux Server 18.04. I've enabled DHCP in PiHole, set Range of IP addresses to hand out, set Router (gateway) IP address, enabled Quad9 upstream DNS server and of course disabled DHCP on m TP-Link C3150 router and saved settings.
I can only gain internet access if a manually configure a static IP on devices. The pihole -d output seems to suggest everything is OK. I just can't figure out why no devices on my LAN can see a DHCP.
Your debug log looks about fine, positively receiving, blocking and forwarding DNS queries, but lists an awful lot of processes grabbing for ports (and you are running nginx instead of lighttpd, but that shouldn't hurt DHCP).
Let's verify your Pi-hole gets proper hold on DHCP ports by executing the following command on your Pi-hole machine:
sudo netstat -nltup | grep 'Proto\|:67 \|:547 '
Also, how are your prospective DHCP clients connected to your network?
Straight to your router, or would you run some additional network equipment, like switches, APs, additional routers?
All prospective DHCP clients I've tested are connected directly to the router over WiFi. There is an extender but that also provides the same results, i.e no IPs assigned.
netstat results shows that Pi-hole is listening for DHCP on port 67, which is in line with your debug log showing you have full IPv4 connectivity. Pi-hole is also the only process on your Pi-hole machine doing so.
I can think of a few reasons why Pi-hole would not be receiving DHCP requests:
a) a firewall blocks DHCP ports on your Pi-hole machine
b) prospective clients are not on the same network segment as Pi-hole (which could be the case if they were not directly connected to your router by LAN or WiFi)
c) another DHCP server is active on your network and preferred by your clients
From a prospective client, you can test how your network reacts to DHCP broadcast messages using nmap:
sudo nmap --script broadcast-dhcp-discover
Please post your results here, preferably by pasting as text.
Among other, results will show the originating DHCP server's IP address as
Server Identifier: 192.168.0.<x>
where we'd expect <x> to match the last octet of your Pi-hole's address, if Pi-hole is indeed your DHCP server.
In absolutely every guide I found regarding enabling DHCP on PiHole, not a single one mentioned having port 67 open. Once port 67 was allowed in ufw, IPs began being dished out to prospective DHCP clients.
