Configuring a WiFi Access Point using Raspberry Pi..... How To with the new kernel

I found a post on nmtui configuration tool that allows AP configuration if you drill down far enough. Still looking for CLI insight.

Talking to myself, not a good thing.

Here is what I have discovered so far.

A fresh install of Raspberry Pi OS Desktop bookworm followed by the string of commands, will create an AP that I can connect to and surf the internet. 

sudo apt update
sudo apt upgrade
sudo nmcli con add type wifi ifname wlan0 mode ap con-name accesspoint ssid "hotspot" autoconnect true
sudo nmcli con modify accesspoint 802-11-wireless.band bg ipv4.method shared ipv4.address 192.168.6.1/24
sudo nmcli con modify accesspoint ipv6.method disabled
sudo nmcli con modify accesspoint wifi-sec.key-mgmt wpa-psk
sudo nmcli con modify accesspoint wifi-sec.psk "hotspot1234"
sudo nmcli con up accesspoint

I can't take credit for the answer, the bulk of the heavy lifting was provided through these articles.

www.baeldung.com/.../nmcli-wap-sharing-internet
forums.raspberrypi.com/viewtopic.php

That being said I still have an unanswered question. The AP distributes IP Addresses to hosts that connect using addresses from the same IP Pool of it's own address. 

How is the DHCP pool determined? That I don't have an answer for at the moment.

Hi Sean,

I've never done this so was curious what commands would be used for it too. Glad you're getting there with the config.

Just out of curiosity, what was the use-case? Is it to create an AP at a location where there is no WiFi but only Ethernet? Or is the Pi connected some other way to the Internet, or not at all, and only used for a LAN with no Internet access?

I've used this (at the time with hostap, not NetworkManager ) when the only solution was to use WIFI (because of the location), but I had no wifi router. A RPi connected to the network as a wifi AP.

For the DHCP server, DNSMasq was perfect.

It worked flawlessly .

You have to distinguish "dchpcd" and "dhcpd".
The former has an additional "C" in its name which stands for client. This is the part that is responsible for asking around what IP your raspberry should use when connected to a network.
This has been replaced by NetworkManager in recent distributions because it can handle a lot of other cases.

The latter is a DHCP server which keeps track of requests made to it for IP address attribution. It listen on network interfaces for specific messages (DHCPREQUEST) and answers them properly. Its configuration is in /etc/dhcpd.conf and you will find inside it the definition for "subnets" into which there are the IP ranges associated with any given interface.

Note that "dhcpd" is not the only DHCP server available, nowadays, it is often replaced by DNSMasq which despite its name does not limit itself to DNS handling but also to DHCP management. A frequent situation where DNSMasq is used is in conjunction with PiHole where it is embedded in the solution.

I was investigating using smart phone to control the operation of a Model railroad engine. Manufactures solutions are expensive.

JMRI an open source CMS for programming the decoders in DCC engines had a solution. https://mstevetodd.com/rpi It was using bulleye Raspbian OS.

I discovered the install on bookworm failed miserably. On investigating I found the implementation of NetworkManager in this release replaces a lot of the old networking configurations.

I found a procedure I used in 2018 that used hostap, dnsmasq and dhcpcd to create AP. Over the years it appears to have been perfected.

I suspect the novice Pi dabbler are going to have difficulties. They will find all these complete procedures for AP setup that won't work on the current OS. That understanding of OS releases and what is supported will bite them in the ***.

I see.. thanks for the explanation! JMRI looks pretty comprehensive. I understand the use-case now. 

dnsmasq is not installed in the Raspbian OS (bookworm).

The modifications to /etc/dnsmasq.conf

interface=wlan0

dhcp-range=192.168.4.2,192.168.4.20,255.255.255.0,24h

That enabled a DHCP IP range is not longer available.

I do have it working using the nmcli commands provided. I just haven't determine (if even possible) how to set the DHCP IP pool range that the AP uses.

If dnsmasq is not installed, then it's most likely dhcpd that is available. In that case, the configuration is inside /etc/dhcpd.conf where you find subnet definitions like this:

subnet 10.10.10.0 netmask 255.255.255.0 {
        authoritative;
        range 10.10.10.100 10.10.10.199;
        option domain-name-servers 10.10.10.254;
        option subnet-mask 255.255.255.0;
        option routers 10.10.10.254;
}

Here, I'm telling the DHCP daemon that for the interface plugged to network 10.10.10.0/254 it should act as an authoritative DHCP server and provide an IP between 100 and 199 (inclusive)

Maybe you have something similar in your case.