Hi, I don't know if this has been reported before. I recently switched from ISC to dnsmasq and today noticed a plethora of log overflow errors, so I attempted to adjust the logging level.
2026-01-20T15:37:42-08:00 Warning dnsmasq overflow: 15 log entries lost
2026-01-20T15:37:42-08:00 Warning dnsmasq overflow: 4 log entries lost
2026-01-20T15:37:42-08:00 Warning dnsmasq overflow: 15 log entries lost
2026-01-20T15:09:39-08:00 Warning dnsmasq overflow: 9 log entries lost
I had enabled "Log DHCP options and tags" and was seeing those when viewing informational logs, so I disabled the option and saved settings. However, the logging did not change.
It appears that no matter what log settings are selected in the configuration, the logging options in the dnsmasq.conf file do not change. Other settings such as 'no-hosts' apply correctl.
/conf/config.xml fragment:
<dhcp>
<no_interface/>
<fqdn>1</fqdn>
<domain/>
<local>1</local>
<lease_max/>
<authoritative>1</authoritative>
<default_fw_rules>1</default_fw_rules>
<reply_delay/>
<enable_ra>1</enable_ra>
<nosync>0</nosync>
<log_dhcp>0</log_dhcp>
<log_quiet>0</log_quiet>
</dhcp>
Code fragment from the template /usr/local/opnsense/service/templates/OPNsense/Dnsmasq/dnsmasq.conf:
{% if dnsmasq.dhcp.log_dhcp %}
log-dhcp
{% endif %}
{% if dnsmasq.dhcp.log_quiet %}
quiet-dhcp
quiet-dhcp6
quiet-ra
quiet-tftp
{% endif %}
Template output from /usr/local/etc/dnsmasq.conf:
log-dhcp
quiet-dhcp
quiet-dhcp6
quiet-ra
quiet-tftp
https://github.com/opnsense/core/pull/9632