Modem limiting max 5 connected

bcake

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Jul 20, 2009
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I've had problems with my Internet for months now. We're 7 computers (wireless) wanting to connect to a modem. The modem a real shitty one that my ISP provided for free, it is also rigged with our ISP's custom firmware preventing me from getting admin access. Problem is that every week one of us can't connect ("limited or no connectivity") to the network.
Last month i got an IT guy to take a look at it, and he said that the ISP limits the amount of computers connected to 5. Not all of us are connected at one given time, but usually we're about 4-5 connected.
I have never heard of a modem limiting the amount of wireless connections. So wanted to check with you guys first. Is this true? If so, what's the fix?
My own solution is to buy a router which I can then configure on my own, but I'm not sure if this will fix the problem as the modem is still rigged. Do I have to buy a new modem too?

Thanks in advance :)
 

eibgrad

Splendid
Just get your own router and chain it to the ISP's modem. Now you're only using one of his 5 valid IP addresses, but sharing it with as many devices as you like behind your own router.

Ideally you'd prefer to put the ISP's modem in "bridge mode" and add your own router, since that avoids a double NAT situation (may or may not be an issue, depends on the application). But if you're not allowed access to the modem by the ISP, then you're limited to chaining routers. Still far better than being limited to a max of 5 IPs.

 

bcake

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I don't get it...I thought a modem could only have one public IP adress. But ok so the solution would be to get my own router. To avoid the NAT issue, do I get a modem as well?

I could just get a router+modem combo in that case.
 

eibgrad

Splendid
Ok, I was making an assumption here and perhaps that assumption was wrong, so let’s examine it more closely.

Yes, normally an ISP will limit you to one public IP. But then you mentioned being limited to 5 IPs. At that point I was assuming that what you have is not just a modem, but actually a combo device, a device that's BOTH a modem+router. This is very common for DSL customers. If that was NOT the case, but it was actually just a pure, simple modem, then we'd have to be talking about 5 ***public*** IPs. That just seems highly unlikely.

So assuming I'm right, assuming that what you have is a combo device, one that's both a modem+router, then presumably the 5 IP limit is for the ****local*** IPs assigned by the router and its DHCP server (e.g., 192.168.1.x). If that’s the case, then by chaining a second router to the combo modem+router, you’re simply sharing one of those local IPs w/ the second router, and thereby no longer limited to 5 local IPs.

[modem+router (192.168.1.x subnet)](lan)<-- wire -->(wan)[your router (192.168.2.x subnet)]

In the above example, let’s say your ISP limits you to the IP addresses 192.168.1.10 thru 192.168.1.14 (5 local IP addresses). And you’re locked out from changing that configuration. By chaining your own router behind it, your router gets one of those IPs for itself (let’s say that’s 192.168.1.10), and then shares that IP address w/ the subnet it’s supporting on the 192.168.2.x. And since you control the 192.168.2.x subnet, you can have as many local IPs as you want. IOW, you’re treating one of the local IPs available from the ISP’s router AS IF it was a public IP and sharing it as you normally would behind your own router.

Of course, if you could just get another modem+router of your own that doesn’t have these restrictions, as long as your ISP doesn’t prevent it.

NOTE: Although you claim the ISP has locked you out, I wonder if you couldn’t simply manually configure additional local IPs on your various devices. I wonder if all the ISP has done is limit the IPs available from the DHCP server of the combo modem+router, but otherwise hasn’t prevent access to more IPs if they don’t rely on DHCP. Just speculating.
 

bcake

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Well, i if the router prevents more than 5 connections in the lan, then sure, i'm limited to 5 IPs.


So this would be the solution? A router isn't enought?

The way i found out about the custom firmware was that i master reset the modem without plugging it into the phone line and i got admin access. But as soon as i plugged it into the wall to get internet, it performed an auto reset and i was back to the rigged custom firmware preventing admin changes.

I also want this solution to enable me to port forward. When i emailed my ISP about them preventing me from port forwarding, i got a reply saying that port forwarding wasn't needed since "it's a modem and all ports are already forwarded"...yet they arent... :heink:
 
G

Guest

Guest
Run ipconfig/all from one of the computers connected to the modem and post the output here.
 

Kewlx25

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Oct 23, 2009
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Some ISPs hand out more than 1 IP address. My ISP use to hand out up to 3. They are random IPs. I'm assuming the OP is actually connecting directly to the cable modem and not using a NAT.
 

jessievaz

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Dec 24, 2012
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HELP!!! I've had the same problem more or less and can't seem to find a solution!

Here are my specifications...
■ZTE router/ modem provided by ISP (in Chile) connected to DSL service
■Apple Time Capsule connected to router/ modem serving ISP addresses through wifi to all my devices

Problem: stuck at a limit of 5 devices ( I have 7) that can be connected at any one time!!! UGH !!!

After reading this post, and a few other related posts I've realised two things:
■Devices list an ISP 192.XXX.1.X (modem/ router assigned) but Time capsule sees them as 169.254.XXX.XXX (self-assigned)
■Devices don't seem to be registering a 10.0.1.X which is normal for apple devices serving ISPs

Have tried everything I can think of to stop the 5 device limit and I'm stuck. Devices can use and see the Internet but only 5 at a time. Reading the post above, I think they're all getting their ISP from the ZTE router and not the Time Capsule at all which is why they are getting limited.

Any advice on how to fix these problems? Thanks!
 

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