This evening I'm going to install pi-hole on my Debian Buster server (static IP). The server currently hosts samba, plex, unifi controller and tvheadend but has spare capacity to run pi-hole as well.
Before I install I want to preserve the current DHCP/DNS settings in case I need to rollback but based on some searches over the last few days I can't nail this down.
At the moment the Debian server does not act as a DHCP/DNS server so only comes with what's part of stock Debian (no desktop). I'm aware that pi-hole will possibly install a different DHCP server but I won't be using it as I wish to continue using the DHCP server on my router and configure all my clients DNS settings manually.
So which DHCP/DNS settings/config files should I be backing up pre-install?
Yes I know, that doesn't really concern me as it seems to be working with recent Ubuntu versions (which are based on Debian Testing), but I may want to roll back so would appreciate some guidance in relation to my question
The DHCP server functionality is part of the dnsmasq implementation included in pihole-FTL. This is not active by default. So, if your router is currently providing DHCP services, this will not change.
Pi-Hole ports are described here - you would want to ensure your existing services on the server will not conflict.
dhcpcd5 might get installed, if not installed already, that could change current configured network settings:
pi@noads:~ $ apt show dhcpcd5
[..]
Description: DHCPv4, IPv6RA and DHCPv6 client with IPv4LL support
dhcpcd is a one stop network management daemon which includes
* RFC compliant DHCPv4 and DHCPv6 clients
* DHCPv6 Prefix Delegation support
* IPv4LL (aka ZeroConf) support
* ARP address conflict resolution
* Link carrier detection
* Wireless SSID profiles
* ARP ping profiles
[..]
In reply to my own post for the benefit of anyone else interested, the installer didn't quite make it to the end on my Debian Buster installation but only 2 things required tweaking.