Hello
I migrated my ISC DHCPv4 configuration to Dnsmasq DNS & DHCP after reading that ISC DHCPv4 is no longer maintained. Everything was fine until I rebooted:
When I reboot, both ISC DHCPv4 and Dnsmasq DNS & DHCP services are started, where Dnsmasq DNS & DHCP fails to start. This makes sense, as both try to bind to port 67 (DHCP). I'm desperately looking for a way to disable the ISC DHCPv4 from booting, but I was unable to do so via UI. The usual menu entry with the interface name is no longer there, the general menu entry as well. I'm also failing to edit my DHCP static host configuration, so after every boot, my servers get wrong IP addresses.
Screenshot_2025-08-14_21-18-03.png
Is there any way I can the ISC DHCPv4 completely? Or is there a way to disable the service via the corresponding service file?
Any help would be greatly appreciated. Thanks a lot.
ISC dhcp does not occupy port 53.
DHCP - Port 67
DNS - Port 53
So probably Unbound.
Follow this:
https://docs.opnsense.org/manual/dnsmasq.html#dhcpv4-with-dns-registration
Thanks for the quick reply. You are absolutely right, this is not a DNS issue, but a DHCP issue.
If I would have read the logs correctly, this would be obvious:
Critical | dnsmasq | failed to bind DHCP server socket: Address already in use
This explains why there is a conflict with ISC DHCPv4 and the Dnsmasq DNS & DHCP service.
On the other hand, this does not solve my problem :-/
Have you tried manually going to services_dhcp.php?if=lan to see if it's just a UI issue? that's the URL for the ISC DHCP configuration page. Replace "lan" with whatever you have called your LAN interface.
Quote from: Stormscape on August 14, 2025, 10:21:07 PMHave you tried manually going to services_dhcp.php?if=lan to see if it's just a UI issue? that's the URL for the ISC DHCP configuration page. Replace "lan" with whatever you have called your LAN interface.
You made my day, I was looking for a deeplink for quite some time already. With your URL I managed to disable the
ISC DHCPv4 service for both interfaces. Everything is working as expected now.
@Stormscape
If you want, please PM me and let me know if you have a Github/buymeacoffee account or similar so I can send you something to express my thankfulness.