My VOIP box is hijacking my network!

Posted on 2008-10-16
Last Modified: 2012-05-05
Can someone give me some advice here& my network is behaving real strangely, and as Ive had a few changes to it, Im not sure whats going on.
Background info (or skip to PROBLEM below).
Im using a Dlink DSL205T Modem with ADSL2 to access the internet, and a Linksys WRT54GS for Ethernet and wireless access. And also a small Linksys VOIP box for calls.
As Ive got Ethernet ports built into my house, I thought Id make use of them.
There are 4 ports in the downstairs office, and 4 ports upstairs (2 in the dining room, 1 in loungeroom, and 1 in bedroom).
Anyways I got it all working the LAN and internet, and it was going great. I plugged the router into the downstairs area, and upstairs the modem (via crossover cable) into the dining room port and patched the downstairs cable into my routers Internet port. This was all good.
**** PROBLEM ****
Ive been having the occasional internet disconnect and as I play poker it was starting to cost me money getting disconnected so much. So I did a bit of reading and figured I should upgrade the firmware on the Dlink modem. So I upgraded that. I also decided to try Tomato firmware (upgraded from DDWRT) on the Linksys.
Now this is where Ive started to have problems. When I boot up my laptops, either the downstairs one which is plugged direct into the Ethernet port of the router, or the upstairs laptop in loungerooom into the ethernet port, they are both assigned IPs in the 192.168.0.x range, where as before they were always assigned 192.168.1.x range. The ip of is actually my VOIP box. So it kind of appears like my VOIP box is taking control of my network and assigning itself as the default gateway for my laptops and giving them IP addresses.
I can no longer access my modem on OR my Linksys on
So to test it my theory if the VOIP box was being a hog, I unplugged it from the network and sure enough my internet and LAN all came back to life. So then I loaded up a game of poker and my internet drops out again! Dammit :(
My voip box is password protected by Engin so I cant get into it either.
How do i stop my voip box hogging my network?
Question by:blueskies77
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Accepted Solution

Gzzrt earned 250 total points
ID: 22735406
You could assign static ip address to all your devices and point them to the dlink modem.  Then turn off dhcp on the modem and see how that works.  The ideal would be to change the settings on the voip box, but if that isn't an option then I would give this other method a shot.

Author Comment

ID: 22738869
thanks for the reply. The problem I have with doing that, is when I plug in the VOIP box it reassigns IP addresses to my connected laptops, in the range of 192.168.0.x , and therefore I cannot access either the Dlink modem ( or the Linknsys router ( .

In the mean time I set up the bridged mode on the ADSL modem, and use the linksys for the PPOE connection. But still the same problem,unfortunately.
LVL 16

Assisted Solution

SteveJ earned 250 total points
ID: 22745706
So you don't want the VoIP box on the same subnet? Why not just reassign the DHCP range on the linksys to 192.168.1.x
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Author Comment

ID: 22755071
well i figured out the problem, after upgrading the firmware on th Dlink modem, I plugged the ethernet connection into the Ethernet port of the VOIP box instead of the internet port. Which caused all sorts of problems.

thanks for the suggestions, i'll award some poitns for effort :)

Author Closing Comment

ID: 31506725
well i figured out the problem, after upgrading the firmware on th Dlink modem, I plugged the ethernet connection into the Ethernet port of the VOIP box instead of the internet port. Which caused all sorts of problems.

thanks for the suggestions, i'll award some poitns for effort :)
LVL 16

Expert Comment

ID: 22758524
Yikes! I hate it when I do that.

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