DHCP lease does not automatically renew.

[tango08]

The DHCP lease on my HP desktop does not automatically renew. The problem started on 9/1/21.  I have had to manually renew the lease twice since then by running CMD.   I did not do any updates around the time the problem started.  The only thing I did was to run the HP hardware diagnostics tool.  I ran the Network Adapter diagnostic tool to see if it detected any problems but it just ran continuously for 30 minutes without giving any results. 

Also, if I restart my pc, it will update the DHCP lease..  

[itsmyname]

@tango08 -- from a command-line, what is the output from: IPCONFIG /ALL ?

It should show the IP-address of the DHCP-server, and the start & end times for the DHCP-lease.

How long (minutes? hours?) is the duration of the lease?

If you power-off your cable-modem, by disconnecting its power-cord, wait a few seconds, and then reconnect the cable, to force it to reboot, does this help? 

Does the date & time & timezone "inside" the cable-modem match the values on your computer? 

[tango08]

The DHCP lease start is 9/11/21     9:50:32 am

The end time is  9/16/21   3:33:51 pm

However, the lease lasts no longer than 48 hours. before I have to run ipconfig, release and ipconfig renew or reboot the pc.

I tried powering off modem as you said but that did not work.

The date on  the modem is correct however the time is incorrect. It shows one hour behind my computer time. 

I would guess that that is probably the problem.  I am not sure how to correct the time on the modem.  I can reset or restore the modem but nor sure if that is the correct thing to do to solve the time error. I have tried to contact the modem vendor, Comcast but the person i have talked to doesn't seem to know how yet.

The comcast modem is:

ARRIS , model TG1682G

Thanks for your help with this. 

[itsmyname]

@tango08 - The date on  the modem is correct however the time is incorrect. It shows one hour behind my computer time.  I would guess that that is probably the problem.  I am not sure how to correct the time on the modem.  

Good guess!

Can you logon to the modem, and reset its "timezone" to match the timezone that your computer is using? Then, power-off the modem (by removing the power-cord) and power-on, and check its date/time.

It is strange that being just one hour "off" on a 5-day lease should cause a problem that forces your computer to be restarted. The "protocol" that your computer should be using is to calculate the date/time when the lease is 50% "consumed", and then send a "DHCP-renew" request. If no response, then your computer should retry later, somewhere about 60% or 70% or 80%. and a few more times up to the 100% level.

Or, just reset the "timezone" on your computer to match the modem's timezone.

[tango08 · Accepted solution]

I am not sure what changed or if anything changed but the problem is no longer occurring.  For the past 2 weeks the DHCP lease has been automatically updating.

Thanks for your help.

[itsmyname]

@tango08 -- Please use "Accept As Solution" if that is the case. This tells contributors that you don't need any more assistance.