How to disable dnsmasq offered DNS service ?

As you know dnsmasq is a lightweight DNS, TFTP and DHCP server. It is intended to provide coupled DNS and DHCP service to a LAN.

[root@humbles-lap qemu]# ps aux |grep dnsmasq
nobody 1992 0.0 0.0 12968 496 ? S Nov21 0:00 /usr/sbin/dnsmasq –strict-order –bind-interfaces –pid-file=/var/run/libvirt/network/ –conf-file= –listen-address –except-interface lo –dhcp-range, –dhcp-lease-max=253

Dnsmasq accepts DNS queries and either answers them from a small, local, cache or forwards them to a real, recursive, DNS
server. It loads the contents of /etc/hosts so that local hostnames which do not appear in the global DNS can be resolved
and also answers DNS queries for DHCP configured hosts.

The dnsmasq DHCP server supports static address assignments and multiple networks. It automatically sends a sensible
default set of DHCP options, and can be configured to send any desired set of DHCP options, including vendor-encapsulated
options. It includes a secure, read-only, TFTP server to allow net/PXE boot of DHCP hosts and also supports BOOTP.

Dnsmasq supports IPv6 for DNS, but not DHCP.

[root@humbles-lap qemu]# netstat -talupan|grep dns
tcp 0 0* LISTEN 1992/dnsmasq
udp 0 0* 1992/dnsmasq
udp 0 0* 1992/dnsmasq
[root@humbles-lap qemu]#

If you want to disable dnsmasq offered DNS and to use your external DNS server , you can do it using port option/flag .. Specify port as “zero” :

-p, –port= Listen on instead of the standard DNS port (53). Setting this to zero completely disables DNS function, leav‐
ing only DHCP and/or TFTP