Connectivity
Connectivity and managing Your Comcast Business network
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Visitor

Not getting an IP address

My Account website says my service is up, the modem's lights aren't showing anything out of the ordinary, but my computer (the Linux server that functions as the router for my network) isn't even getting an IP address.  Tried power-cycling the modem and the computer to no avail.

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Trusted Forum Contributor

Re: Not getting an IP address

Here are some simple diagnostic hints:

 

1.  Connect a different single system, not your Linux box, directly to the modem. The system should be configured for automatic address configuration (DHCP).

2.  Cycle the Modem power.

3.  Wait for the Modem to be reconfigured.

 

If your different single system does not eventually get an IP address, it is time to call Comcast. But, Wait...

 

Before you call Comcast, try using your browser to access the Modem management pages and print the various tabs for reference while talking to Comcast.

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Visitor

Re: Not getting an IP address

Yeah, tried that, and replacing the network cord, too. And disconnecting the house from the other network port.

 

Unfortunately, my router is in bridging mode, so I can't log in to the router.

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Trusted Forum Contributor

Re: Not getting an IP address

Apparently you have a Comcast-supplied Modem/Router.

 

Comcast support number is  1-800-391-3000.

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Visitor

Re: Not getting an IP address

Yep, I do.

 

Just got off the phone with them.  She switched it from bridging mode to "normal", and I could get an IP address fine.  It just failed when in bridging mode.

 

Bridging was easier for my network, but I think I can deal with this setup by putting my home server on the DMZ, and changing my dynamic DNS service to use an external website instead of updating all of my DNS records with a 10.* address.

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Trusted Forum Contributor

Re: Not getting an IP address

Hello CyberKnight and welcome,

 

If your Linux Server network configuration is setup for dynamic IP access and is not using a staticIP address, then I would recommend that you use 10.1.10.2 through 10.1.10.9 for your dedicated network IP address. This is predicated on your Comcast Gateway's (CG) LAN DHCP server is default configured for the dynamic range of 10.1.10.10 through 10.1.10.199.

 

Your Linux Server NIC MUST be Enet connected to one of the CG LanPorts 1-4 for it to use one of the above recommended IP Addresses. Could you tell us a little more about your nextwork configuration because if your Linux Server is providing your intra-network DHCP Server, then you may be in a DHCP conflict situation. But this is not clear until you clarify.

 

Hope this helps you out. 

 

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