Odd dnsmasq lease time behavior on 386.3_2 and ASUS GUI.

Tvbaas

Occasional Visitor
For the record I am running a mesh configuration of an AX88u main router on Merlin 386.3_2 and an AC68u as a mesh client running on stock 3.0.0.4.386_46065. Also a Open vpn server is active on the AX88u.

According the change log for 386.3_2 , dnsmasq version 2.85-openssl is used.

In the Asus Gui DHCP lease time is set as :
ASUS_DHCP.JPG
I just noticed a odd behavior of the DHCP lease time when monitoring the dnsmasq logfile.

In dnsmasq.conf the lease time is set as :

dhcp-range=lan,192.168.50.150,192.168.50.200,255.255.255.0,960s

When looking at the dnsmasq logfile, I grabbed for DHCPREQUEST for one client:

Feb 3 10:22:58 dnsmasq-dhcp[3077]: DHCPREQUEST(br0) 192.168.50.174​
Feb 3 10:30:58 dnsmasq-dhcp[3077]: DHCPREQUEST(br0) 192.168.50.174​
Feb 3 10:38:59 dnsmasq-dhcp[3077]: DHCPREQUEST(br0) 192.168.50.174​
Feb 3 10:46:59 dnsmasq-dhcp[3077]: DHCPREQUEST(br0) 192.168.50.174​
Feb 3 10:55:00 dnsmasq-dhcp[3077]: DHCPREQUEST(br0) 192.168.50.174​
Feb 3 11:03:00 dnsmasq-dhcp[3077]: DHCPREQUEST(br0) 192.168.50.174​
Feb 3 11:11:00 dnsmasq-dhcp[3077]: DHCPREQUEST(br0) 192.168.50.174​
Feb 3 11:19:01 dnsmasq-dhcp[3077]: DHCPREQUEST(br0) 192.168.50.174​
Feb 3 11:27:01 dnsmasq-dhcp[3077]: DHCPREQUEST(br0) 192.168.50.174​

The time between these requests is not 16m as expected but only 8m.

When changing the lease time in the ASUS GUI, dnsmasq will always use half of the set lease time for a DHCPREQUEST!!

Something similar is going on in the Asus Gui.
Looking at the DHCP leases log , it will start at 16m and counting down, but will not go down below 8m!
ASUS_DHCP2.JPG
Can anyone else confirm this odd behavior in the newer firmware (updated dnsmasq ) or is it as intended?
 

dave14305

Part of the Furniture
That’s how it works. Clients renew when the lease is half over, assuming the client is up and running at that time. I don’t think there’s been any change in behavior on dnsmasq’s side, but perhaps some of your clients have changed their renew behavior since the clients initiate the renewal process, not the server.
 

Tvbaas

Occasional Visitor
That’s how it works. Clients renew when the lease is half over, assuming the client is up and running at that time. I don’t think there’s been any change in behavior on dnsmasq’s side, but perhaps some of your clients have changed their renew behavior since the clients initiate the renewal process, not the server.
Thanks for the explanation, didn't know this is normal operation of dnsmasq.
 

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