Max arbitrary number of DHCP IPs due to bug in my Shaw Modem

Much like our WD cloud that is full of bugs written by buggy programmers, my LAN was exhibiting a very strange problem last year with my Smart TV unable to connect to the internet for Netflix every couple of weeks. This was the same with my iPhone, iPad, Apple TV of which once in a while it could not connect to the internet because I was unable to get an IP. I say last year because I managed to work around the problem and it isn’t the solution that I’m posting up but mainly to warn you that these buggy modems are becoming more ubiquitous.

The problem with these modems is that they are now the all-in-one box that cable/phone companies installs into your home. They are your gateway, the DHCP server, the firewall, the Wifi provider and we never blame the modem for any of our problems thinking that they work exactly like the old counterpart that they replace.

Suddenly your cloud doesn’t work anymore and of course the first thing WD says, sure send it in and we will replace it, even though it has nothing to do with your cloud. Remember how you would lose connection to your cloud; yup it is your modem fault (well most of the time anyways).

Reserves doesn’t really work on my Shaw Hiltron CGNM-2250 Wireless Modem Firmware. Of course I didn’t really know that before because it works sort-of as I could see it working on my Clouds but not on my Windows 10 PC; it almost works on my TP link Cameras. Yes, of course I made sure that my DHCP range was not in the DHCP Reserve Range although I did try reserving an IP that was assigned by DHCP and that didn’t work either.

If you re-boot the modem every week, almost every device is happy, that is until I turn on the security cameras of which the next time you try to watch Netflix, you can’t; as it waits forever to acquire an IP.

This drove me nuts for over a year and I had the same problem after swapping the modem for a new one; much like WD would swap your clouds but the problem was in the firmware.

Of course, most users won’t have any problems since they probably only have one, two or three devices connected.

I have a lot of Wifi connected equipment like 8 x light switches (Lutron) with a Bridge box, 6 x iHome smart outlets that turns on/off my TP link security Cameras, 6 x TP link Cameras themselves, Airport extreme, Airport express forming a bridge for more wired ethernet devices on the other side but the two Airport devices are Wifi connected, 2 x Apple TVs, 2 smart TVs, Sony Playstation, Nintendo Switch, 3DS, 2 x iPads, iPhone, MacBook and a Windows 10 PC for recording the Camera streams. I may have a few other forgotten Wifi connected IPs like my gaming PC that I turn on a few times a year now that all my gaming has moved to my Playstation. There is also my Ring Doorbell and… oh yeah, my Wii U…

So finally, one day, I decided to turn off DHCP on my modem and delete all my reserves; making my modem simply a gateway. I then turned on my Apple Airport Extreme DHCP instead. One by one, I went through my devices to set static ips on the devices themselves for the ones that needed them, like my Clouds, my TP Link Security cameras, my mac mini server and the rest I just let my DHCP assign an IP to them.

To my relief it just worked (Apple :slight_smile: ) and It has been half a year now and I haven’t had to reboot my modem nor any of my devices.

The beauty to moving my DHCP server to my Airport Extreme is that I can replace my modem anytime without any of my devices being affected. In fact I could move from Shaw to Telus as my internet provider without any of my devices blinking a LED.

I could ask Shaw to switch their modem over to Gateway mode (passing the WAN IP directly) so that my Apple Airport Extreme becomes the main router but it is working fine and port mapping and firewall are still functioning fine on the modem itself.

IMHO one should never use the vendor supplied gateway as your LAN router. You should always add your own device and shut off the vendor’s WiFi and DHCP. That way you control your own network (much as you did with the Airport Extreme). I use 2 ASUS routers + a couple of gigabit switches and have never had any device drop-out.

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Well, it’s an option if the router you are supplied with is a bit rubbish. I haven’t had many problems with the one my ISP supplied, and I have full control over it. It’s just a bit old now…

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Pfft. The ADSL modems supplied by my carrier (CenturyLink) are terrible. I put them into dumb gateway mode, then put a much better router right after them that does the actual firewalling and such.

What I usually do is change the pool size of the DCHP server so that it only doles out 128 IPs, instead of the full 255 (remember, x.x.x.0 is local multicast, and reserved.) I then put certain devices with static IPs, (Rokus, the MyCloud, game consoles, etc) that are not in the DHCP pool range, so that they always have a valid IP, and wont get walked on-- while leaving a nicely sized pool for transient devices. (Laptops, phones, etc.)

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