AX86U MAX DHCP LAN lease time

[frequenzy]

I just got a AX86U router to replace my AC68U. I installed Merlin 386.3_2 then factory reset to default. Now I'm trying to configure DHCP lease time, my old setup is set to 2592000seconds = 30days. It doesn't let me enter it on the AX86U.

Any suggestions? Can it be done via NVRAM cli? Are the new beta/alpha firmwares support the 30days DHCP lease time?

 

[ColinTaylor]

Why do you need such a long lease time?

 

[frequenzy]

Why do you need such a long lease time?

I prefer all the clients not to change ip's frequently, since I tag each device via their ip on AdguardHome. I know I can assign them static ip via dnsmasq but it's not really practical if I need to list down more than 40+ devices.

I just wonder why longer lease time is not supported on the AX86U.

 

[ColinTaylor]

It's a change that was made back in February 2020 in the previous 384 codebase. You must have been running a very old firmware version, or not attempted to change that value since then.

Having a maximum lease duration of 7 days rather than 31 is not normally a problem as clients will renew their existing lease. In other words, their IP address doesn't change. Having very long lease durations can actually create problems on busy networks by causing the router to run out of leases.

If you really want to change it you could use the following commands:

nvram set dhcp_lease=2592000
nvram commit
service restart_dnsmasq

 

[eibgrad]

FYI. Even if the lease expires, the chances are very high any given client will receive the same IP address anyway, since by default, DNSMasq chooses the IP address based on a hash of the MAC address. You would actually have to add the following directive to DNSMasq to force it to choose the IP sequentially (then you would have an issue).

dhcp-sequential-ip

That said, it's better if the lease is renewed in time.