mjhjmtu

I am trying to setup dnsmasq to act as DHCP server for a hostapd-based WiFi hotspot.

When client connects WAP2 negotiation succeeds, but dnsmasq consistently outputs the following errors.

[ 2081.576809] DHCP[wlan0] - DISCOVER [TX][ 2081.580476] 
[ 2081.582008] DHCP[wlan0] - DISCOVER [RX] 
dnsmasq-dhcp: no address range available for DHCP request via wlan0 
[ 2085.297432] DHCP[wlan0] - DISCOVER [TX][ 2085.301107] 
[ 2085.302630] DHCP[wlan0] - DISCOVER [RX] 
dnsmasq-dhcp: no address range available for DHCP request via wlan0 

These usually mean the configured range is incompatible with device settings.

If this is the case I fail to understand why.

My test dnsmaq.conf is very basic:

root@imx8qxpa0tcuap:~# cat /etc/dnsmasq.conf 
domain-needed 
bogus-priv 
interface=wlan0 
dhcp-range=192.168.207.20,192.168.207.50,12h 

... and current net settings should be compatible:

root@imx8qxpa0tcuap:~# ip addr show wlan0
5: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP 0
 link/ether a0:cc:2b:a5:e0:05 brd ff:ff:ff:ff:ff:ff
 inet 192.168.207.1/32 scope global wlan0
 valid_lft forever preferred_lft forever
 inet6 fe80::a2cc:2bff:fea5:e005/64 scope link
 valid_lft forever preferred_lft forever
root@imx8qxpa0tcuap:~# ip route
192.168.207.0/24 dev wlan0 scope link

Initial dnsmasq printouts show no problem:

root@imx8qxpa0tcuap:~# dnsmasq -d
dnsmasq: started, version 2.78 cachesize 150
dnsmasq: compile time options: IPv6 GNU-getopt no-DBus no-i18n no-IDN DHCP DHCPy
dnsmasq-dhcp: DHCP, IP range 192.168.207.20 -- 192.168.207.50, lease time 12h
dnsmasq: reading /etc/resolv.conf
dnsmasq: using nameserver 8.8.8.8#53
dnsmasq: using nameserver 8.8.4.4#53
dnsmasq: using nameserver 2001:4860:4860::8888#53
dnsmasq: using nameserver 2001:4860:4860::8844#53
dnsmasq: read /etc/hosts - 6 addresses

What am I doing wrong?

Note1: in this test setup the WiFi Hotspot goes nowhere (yet) only communication between client and Hotspot itself are supposed to work.

Note2: the machine is a custom board (i.MX8) running a Yocto based distribution.

Your wlan0 interface network mask is wrong.

-->>> 192.168.207.1/32

A /32 network mask has 32 bits, 255.255.255.255 which is the whole IP address.

You probably meant 192.168.207.0/24 e.g. 255.255.255.0 aka a C class network address. A /24 mask allows you to serve up to 254 IP addresses, from 192.168.207.1 to 192.168.207.254.