This I have a sub-net of cameras on 252 that are prevented from connecting to the internet, where the DSL router is at 254.
$ ip address show dev eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
link/ether dc:a6:32:c4:2f:bc brd ff:ff:ff:ff:ff:ff
inet 192.168.254.123/24 brd 192.168.254.255 scope global eth0:1
valid_lft forever preferred_lft forever
inet 192.168.252.123/24 brd 192.168.252.255 scope global eth0:2
valid_lft forever preferred_lft forever
inet6 fe80::2ab4:46ee:68a2:8f7e/64 scope link
valid_lft forever preferred_lft forever
Now I want to turn on the pi-hole DHCP server, and have it serve out a mask other than 255.255.255.0 and disable the DSL DHCP, but get errors:
DNSMASQ_WARN dnsmasq warning:
using interface eth0 instead
DNSMASQ_WARN dnsmasq warning:
DHCP packet received on eth0 which has no address
No DHCP context has been configured for this interface. Check your DHCP settings.
$ sudo pihole-FTL dhcp-discover
Scanning all your interfaces for DHCP servers and IPv6 routers
Timeout: 6 seconds
Error: Could not bind socket to interface eth0:1 (No such device)
Error: Could not bind socket to interface eth0:2 (No such device)
No answer on eth0:2
No answer on eth0:1
$ sudo grep dhcp /var/log/pihole/pihole.log
Feb 11 12:19:59 dnsmasq-dhcp[751]: DHCP, IP range 192.168.252.17 -- 192.168.252.23, lease time 1h
Feb 11 12:20:40 dnsmasq-dhcp[751]: DHCP packet received on eth0 which has no address
Feb 11 12:20:41 dnsmasq-dhcp[751]: DHCP packet received on eth0 which has no address
So is the dual-address naming a problem, or something else I’m missing?
This seems to be a network configuration issue rather than a Pi-hole one.
You should probably be aware that dhcpcd isn't used anymore by RaspberryPi OS since RPi OS 12/bookworm. Depending on your OS release, dhcpcd.conf may be without effect.
Even if it would be, dhcpcd would only configure network details (like IP address assignments) for existing interfaces. Specifically, it would not create interfaces itself.
And it would seem that something didn't get created as intended, as your ip address output doesn't list an un-aliased IP for eth0.
Furthermore, that output suggests you're managing those additional IPs via long obsolete IP-aliasing from net-tools, instead of adding them via iproute2 commands.
Given your intention of running Pi-hole as DHCP server for several VLANs, just adding additional IP addresses to an interface may not be adequate anyway.
Depending on how your router would handle those VLANs, and how your RPi is connected to your router, you may have to tag your IP addresses accordingly, and/or create additional virtual interface devices (not just IPs).
All of the above would be completely out of Pi-hole's scope.
My Raspbian version is 10.13 with kernel 5.10.103-v7l+. I can accept the problem is with the network configuration and not specifically pi-hole. I just need to get my dhcpcd.conf edited correctly then.
As I understand it, I have one interface, eth0 , with 2 addresses, that is called an aliased IP? I don’t have the router configured as a vlan, that would block what I’m doing. The switch is only routing 2 networks to various locations. pi connects to both, I connect to both remotely, but the cameras aren’t told how to get to the internet.
I’ll go search for iproute2 commands and how to create a correct alias.
I don’t know what a correctly aliased ip address needs to look like to work.
You cant serve different DHCP scope's/ranges from a single physical interface bc of the broadcast nature of DHCP packets.
Either you add physical interfaces (one for each scope/VLAN),
or create virtual VLAN aware interfaces and configure the single connected switch port for "tagged" traffic. iproute2 examples below for configuring reboot persistent via ifupdown(3), or systemd-networkd(4), or NetworkManager(5.1) but no dhcpcd:
I should’ve said, I’ll go work on this, fearing that referenced a newer package.
Yes I do have iproute2 and am using ip
I edited dhcdcd.conf, removing 5 lines but editing almost nothing, added dhcpcd.enter-hook which was not in examples I had previously searched, and restarted dhcpcd.service, pihole-FTL, and now it works.
$ sudo pihole-FTL dhcp-discover
Scanning all your interfaces for DHCP servers and IPv6 routers
Timeout: 6 seconds
Error: Could not bind socket to interface eth0:2 (No such device)
* Received 303 bytes from 192.168.252.123 @ eth0
Offered IP address: 192.168.252.22
Server IP address: 192.168.252.123
Relay-agent IP address: N/A
BOOTP server: (empty)
BOOTP file: (empty)
DHCP options:
Message type: DHCPOFFER (2)
server-identifier: 192.168.252.123
lease-time: 86400 ( 1d )
renewal-time: 43200 ( 12h )
rebinding-time: 75600 ( 21h )
netmask: 255.255.252.0
broadcast: 192.168.254.255
dns-server: 192.168.252.123
domain-name: "lan"
ntp-server: 192.168.252.123
router: 192.168.252.123
--- end of options ---
Received 1 DHCP (IPv4) and 0 RA (IPv6) answers on eth0
No answer on eth0:2
No I don’t have 8021q module installed. Yes I understand DHCP broadcasts to 0.0.0.0 and I can only have 1 server on the visible network. This is fine for what I’m needing. I can continue tinkering with it, since eth0:2 has persisted past the restart despite not being in either conf file, (but not reboot, yet).
$ apt show vlan
[..]
Description: ifupdown integration for vlan configuration
This package contains integration scripts for configuring vlan
interfaces via ifupdown (/etc/network/interfaces).
For further details see vlan-interfaces(5) man page in this package.
.
Please note that these integration scripts only supports a limited
set of interface naming schemes, which means you might be better
off with writing your own ifupdown hooks using ip(route2)
directly in /etc/network/interfaces rather than using this package.
.
It currently also ships a wrapper script for backwards compatibility
called vconfig, that replaces the old deprecated vconfig program
with translations to ip(route2) commands.
This compatibility shim might be dropped in future releases, please
use ip(route2) commands directly.
.
Your kernel needs vlan support for this to work, see "modinfo 8021q".
No, the (obsolete) method of adding those and labelling them with alias interface names (like your eth0:1 as an alias for 192.168.254.123) is called IP-Aliasing.
If you'd add IPs to an interface with iproute2 commands, they'd show up as secondary IPs without an alias.
But for vlans, you'd typically use proper virtual interfaces (which can be created via iproute2 commands) , rather than just adding additional IPs.
However:
You'd need a router with VLAN support to manage VLANs.
If your router doesn't manage VLANs, then I'm neither sure whether you'd actually require VLANs, nor what exactly you would try to achieve.
Are you perhaps just trying to turn your Raspberry Pi into an AP (access point) for your cameras?
You should note that network configuration has become quite convoluted with the latest Raspberry Pi OS Trixie image, as RPi devs have decided to use netplan as the main network management tool, where netplan would generate configuration files for NetworkManager, and they ship a NetworkManager edition that is hard-coupled with netplan, so you wouldn't be able to use dhcpcd or systemd for network configuration OOTB.
Furthermore, RPi OS has also changed their 1stboot configuration to cloud-init.
You should be extra careful about picking your imaging tool to write your sd card.
It's probably safer to use the most recent RPi Imager 2 to write your SD card with Trixie and above, while keeping to use 1.9.6 and below to burn Bookworm and below images, or you may end up with undefined RPi OS behaviour (e.g. no ssh login, despite enabling ssh in RPi Imager).
The whole Raspberry Pi OS story keeps getting weirder and weirder
I see more and more reasons to ditch it completely !!!
But to give you some info about what I would do in this case :
If you can remove Netplan in Ubuntu completely then you should be able to do it in Raspberry Pi OS too IMHO
I build those myself anyway so that should not be an issue…
However I do see more and more reason to finalize my SystemD Networking HowTo document on GitHUB
That has become a “Shitshow” anyway the last couple of years so what I did the last two times was simple and very basic :
Write the image to the microSDXC card with DD on my Linux laptop.
Boot the thing in my secondary Raspberry Pi 3B and configure everything with a keyboard and monitor attached.
I am getting tired of their nonsense more and more so it’s time to consider buying more cute little Intel Atom NUC’s instead of anything Raspberry Pi related
Some people even give away the older models for free so if you can find one… DO IT! LOL!
