Has cable modem got DHCP server?

[whi5tler]

Hi all,



Have been pulling my hair out all weekend with this problem. I am running the standard ntl business 200 cable modem. To this I have a 54g Belkin router. To the router I then have a IP camera with a local IP address of 192.168.2.12 I have set this at my DMZ on my router. When I look at my router setting the Wan Ip is saying 192.168.0.3 and the Default gateway the same. This means that I can't access the IP camera from the internet.



I have tried this exact setup in my house with the old Surfboard cable modem and it works fine. The only conclusion I can come to is that the cable modem has a DHCP built into it and it's giving the router the IP 192.168.0.3. In my house I have the standard 80.*.*.* IP that ntl gives out as the WAN Ip and default gateway. Apart from me not being able to see the IP camera everything is working fine I can surf the internet receive mail and everything.



Any help with this would be much appreciated as my sanity depends on it!



Stacey

[BBKing]

It's a genuine business modem is it? That would presumably be a 2020 rather than a 200, but the differences are trivial.

The business service has a number of weirdnesses that set it apart from the residential service.

Is the WAN port on the router set to DHCP? Does it report what gave it its DHCP address? What does plugging in a straight PC ethernet interface set to DHCP and rebooting the modem result in?

[conor123]

The ambit modems do have a built-in dhcp server (as do the surfboard modems).

Does the PC pick up a valid IP address if you plug it directly into the cable modem or do you still get a 192 ip?

Has the cable modem locked on, or is the coax cable/connection loose?

[whi5tler]

I dont know what would happen if i plugged a PC in but will try tomorrow. Can you turn the DHCP off?

[whi5tler]

Ok here is the Ipconfig when i plug a PC into the Cable Modem

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Intel(R) PRO/100 VM Net
Physical Address. . . . . . . . . : 00-02-A5-**-**-**
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . . . . . . . . . . : 192.168.0.3
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.0.1
DHCP Server . . . . . . . . . . . : 192.168.0.1
DNS Servers . . . . . . . . . . . : 194.168.8.100
194.168.4.100
Lease Obtained. . . . . . . . . . : 07 March 2005 20:14:13
Lease Expires . . . . . . . . . . : 07 March 2005 21:14:13

Also the earlier post was correct about the modem it is a Ambit 2020. Has the modem got a built in router, DHCP or firewall?

[purenuman]

Router firewall problem?

http://www.portforward.com/belkin/f5...forwarding.htm

[whi5tler]

Nope tried opening all the ports and setting as DMZ

[handyman]

you'll no doubt be broadcasting on a set port. Find out which port it broadcasts on and then go to virtual servers in your router settings and forward exp. 81.40.5.2 port 6000 to 192.168.2.12 port 6000. then when you enter 81.40.5.2:6000 into your browser your ip cam should show. ;-)
__________________

Originally Posted by whi5tler

Also the earlier post was correct about the modem it is a Ambit 2020. Has the modem got a built in router, DHCP or firewall?

Modem alocates the ntl ip to the router via ntls dhcp server. router needs that ip pointing to the virtual (private)ip of your camera. Its the same if you want to get vnc working trough the router you just need to tell it which port on which ip that particular request need to go to.

hth

mark

[slimshady]

whi5tler - some of the ntl business cable modems seemed to have nat configured on them, never worked out how to turn it off and i was on their tech support, but it might be worth logging a call with them anyway. I reckon they have turned nat on this particular modem. I think it was in relation to whether you had a single ip account or a five ip account but I can't remember it all. Give them a call anyway.