I installed openWrt just a few days ago and it's simple great. But I have this little problem. When the "lease time remaining" finish (12 hours) the host lost its internet access and I have to switch off and on the router. Is there any way to do that automatically?
Thank you in advance.
DHCP clients should take care of themselves. When the lease time gets near the end, they should reach out to the server and ask for renewal without any special configuration. OpenWrt behaves well as a client, as well as a server.
Would you be more specific about the problem you're seeing?
Is it the OpenWrt router that loses its lease from the ISP, or your own clients that lose the lease from the OpenWrt router?
Most DHCP client implementation ask for a renewal of their DHCP lease at half of the lease time. As mentioned by jeff, it's up to the client to reach out and actively request/ renew the DHCP leases - the DHCP server's job is merely to grant the lease (assigning an IP address) and to maintain the mapping between MAC- and IP address. In case of sleeping/ hibernating clients it's more likely to see problems, but it's still the client's task to engage with the DHCP server in order to re-establish the network connection.
You both were right. After 12 hours of leasing, my computer didn't renew its lease. It was not the openWrt Router. I was confused. Thank you for your fast answers.