How to restrict use of cable modem internet wi-fi?

We have cable modem internet service for our desktop computer. With password another device in the home can receive the wi-fi signal. There is no router and the wi-fi signal comes from the modem which is plugged in to the wall 24/7. We turn the desktop pc off at night.
We need to limit the wi-fi to 11pm cutoff to 7am start. I had a simple timer plugged into the wall and the modem cable was plugged into that and the timer let the modem go off at 11pm and on at 7am. The timer failed to prevent the guest from changing the setup.
There is another closed question about a lockbox, how to secure the cable modem or timer so no one can unplug the setup and then plug the modem into the wall socket for 24 hour access. So no need to repeat the content in that other question.

Windows 7 desktop and parental controls would only limit access to the desktop pc.
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JohnBusiness Consultant (Owner)Commented:
To change the Modem settings means you must log into it. Change the password / set the password so only you have access to it. That will stop anyone from changing the settings.  That should work and is how I manage network devices.

Once secured, you can turn off the service with the timer again.
andyalderSaggar maker's framemakerCommented:
We need to know make/model of cable modem and wi-fi router.
JohnBusiness Consultant (Owner)Commented:
A good Wireless setup (I am not sure about your ISP modem) will have Time of Day settings for Wireless use.
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John Hurst made a good point.

However while your modem might not provide TOD (Time of Day) operation settings it may have a "Access Restriction" option where you might be able to block access to the other computer based on schedule

More information regarding your setup, IE: Type of modem will be helpful

Fred MarshallPrincipalCommented:
I would probably call the ISP interface device a "modem/router/access point" just to cover all the bases of modem, routing capability including NAT that provides you with private IP addresses and WiFi.

With all that capability, you should be able to make settings in the device.
Presuming that you're using "get an address automatically" on the PC, you can run this command prompt command:

The result will tell you, among other things, the Gateway address which should be the modem/router.

With the gateway address, open a browser like Internet Explorer or Google Chrome or Firefox and put that Gateway address in the URL address space in the browser window and presee <enter>.

The modem/router interface should appear and you will probably have to log in.
Either the device has its login information on a sticker on the bottom or more likely with the model number you can find the default login using Google.   Try that to log in.

Once you have logged in, you can change the WiFi passphrase to something unknown to the Guest.
Maybe you can set up a guest network with a different passphrase and with allowed hours.

It would help to have the model number as previously requested.

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nickg5Author Commented:
There is no router. When my desktop computer is turned off, the cable modem is still on 24 hours a day and plugged into a wall outlet.
The wi-fi signal comes from the modem and my desktop system is not related at all.

Arris DG860
andyalderSaggar maker's framemakerCommented: looks like the page you want, add the MAC addresses of your family PCs to the trusted list so it does not apply to them. Add "all" as websites and set the scheduler to block after hours.
nickg5Author Commented:
I looked in Control Panel on the W7 system. I looked in devices and device manager. I see no Arris.
The modem feeds the signal to the pc through an ethernet cable.
I see no buttons or any way to access any settings in the Arris.

The instructions on that screen shot are not found.

JohnBusiness Consultant (Owner)Commented:
They (ISP) should have given you a document to log into the Arris modem with a browser  (192.168.x.y) and manage it that way.

How did you set up the wireless in the first instance.
andyalderSaggar maker's framemakerCommented:
The IP address is your default gateway, get that by running IPconfig in a command prompt. If your ISP set it up for you you may have to ask them to change the settings. You then go to that IP address with a browser.
nickg5Author Commented:
The guest has an Apple laptop. I had never used the wi-fi before and did not know my home even had it. Once the person turned their laptop on and went to connection or network lower right and entered the password given to me by the ISP they had wi-fi.

I could get the password changed but then they would not have access to any wi-fi. i do not think I can control their laptop using my pc or the modem other than cutting the power to the modem using timer, etc.
I asked the ISP if they could put the cable modem on a timed schedule and they do not offer that service.

I put the modem on a timer and when I was out of town Feb. 24th the person unplugged it from the timer. Then when I found out 4 days later that they had done that I used cable tys (same as police use to handcuff people with plastic tyraps) to tighten the cable modem cable to the 6 foot extension cord. No physical way to merely pull the cable modem power cord out of the extension cord. And the timer itself was well hidden. I go out yesterday and when I come back the person removed the traps with some method such as scissors. They actually said they removed them with their teeth. Lucky they were not electrocuted.

I had to get up last night at 1am and remove the cable modem cord and take it my room to stop the wi-fi. Only certain persons can discipline this person. I tried with a timer and they tampered with it. I again hooked it to the timer and secured the two cords by bending them and securing with cable tys. These were removed.

This problem was not envisioned when we (three persons) agreed to wi-fi and gave the person the password.
JohnBusiness Consultant (Owner)Commented:
It seems you need to change the wireless password to something the guest does not know
nickg5Author Commented:
IPconfig gets me a 0.5 second glimpse at the window and it closes immediately. W7 is not allowing the IPconfig window to stay open.
andyalderSaggar maker's framemakerCommented:
I think you're going to have to ask the ISP to remote into your PC and set the modem/router/gateway up for you, restricting access from their end may not be a service they offer but they probably have some support guy who will show you how to configure rules on the integrated firewall. The password you use to configure it through the web GUI isn't the same as the wi-fi password so there's no need to tell that to the guest.
JohnBusiness Consultant (Owner)Commented:
You need to open cmd.exe and run the command from within the window for it to stay open
andyalderSaggar maker's framemakerCommented:
start run and type CMD then type ipconfig in the box that pops up.
Fred MarshallPrincipalCommented:
The modem feeds the signal to the pc through an ethernet cable.
If you do as I suggested earlier, you may be able to access the modem control panel using a browser on your desktop.  If you haven't tried to do this then you may be missing the easiest solution.

Run cmd
Run ipconfig
Get the Gateway address ( it may be or or ........)
Open a browser.
Type the gateway address from above in place of where you see something like "http......" in the browser URL address space.
The modem control panel login should at least appear at this point.
nickg5Author Commented:
I called the ISP and though they do not offer tech support on such issues they were kind enough to give me the MAC address for the guest laptop and my desktop. I'll close this question and begin a new one on how to proceed. Thanks.
JohnBusiness Consultant (Owner)Commented:
If you want a brute force idea, there should be a small hole in the blade of the cable modem plug. Get a small lock to fit through the hole, unplug the modem and put the lock in. That should deter people.
nickg5Author Commented:
John: Good idea to consider.
They actually said, maybe falsely, that they used their teeth to remove the cable ties. Somewhat dangerous maybe.

ISP said the Arris modem is basic and they do not have time controls or access restriction and said to consider a Netgear router that has the specific feature we want like off 11pm and on 7am.

But they also said the person can use Google to find a way to default the router back to the original name using a paper clip and to prevent that we'd have to remove the sticker that has the original name.

They spoke of the filters in the Arris settings and I got as far as the correct MAC addresses and stopped going any further.
They said the filters would not do what we need.
JohnBusiness Consultant (Owner)Commented:
Get a good small lock and they would need hardened steel side cutters to maybe get through it.
andyalderSaggar maker's framemakerCommented:
The ISP saying it is a basic modem does not tie in with the screenshot I posted a link to but admittedly they could reset it to default with a paperclip.

BTW, I sometimes use my teeth to remove cable ties.
nickg5Author Commented:
JohnBusiness Consultant (Owner)Commented:
Thanks, Nick and I was happy to help
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