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Correct router configuration for a DPC3939B in 'Bridge Mode'

Hello Everyone!

I've PM'd Comcast_John for assistance but I thought I'd post here too while waiting for his reply.

My Comcast Business was installed last week (phone + internet). As part of the work, the DPC3939B was placed in 'Bridge Mode'. I don't have a static IP assigned to me (at least thats what I think) by Comcast but my personal DLink router was setup using a Static IP Configuration. It worked until yesterday when I can't get any traffic going into the DLink router.

I can only connect to the internet via hard wire Ethernet connection to the DPC3939B device.

Question: What is the correct configuration for the DLink router - should it be Static IP or DHCP?? And what's the IP addresses (WAN IP, Gateway, DNS) should I use?

Please advise.

Thanks!

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Occasional Visitor

Re: Correct router configuration for a DPC3939B in 'Bridge Mode'

I set the DLink router to DHCP and restarted it.

 

And no luck ... it shows I'm connected to the wireless connection but I can't access the internet. I beginning to wonder if some setting (firewall maybe??) got missed while configuring DPC3939B into Bridge Mode.

 

Is there a way to access DPC3939B if its in Bridge Mode? If so, which settings should I check for?

 

Thanks!

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Community Manager
Community Manager

Re: Correct router configuration for a DPC3939B in 'Bridge Mode'

HI Slydell.  Thank you for the info.  The device is operating in true bridge mode and all router functions are disabled. With the WAN interface of your router set to "obtain IP address automatically (DHCP) it should obtain the public IP address from the Cisco.  Can you access the Internet with a device connected to the D-Link via an Ethernet port on the D-Link router?

 

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Community Manager
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Re: Correct router configuration for a DPC3939B in 'Bridge Mode'

HI Slydell.  Those are the correct DNS settings.  Let us know the results when you connect a PC directly to the Comcast gateway.

 

Thank You

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Trusted Forum Contributor

Re: Correct router configuration for a DPC3939B in 'Bridge Mode'

With the DPC in bridge mode, it acts as a standard cable modem you could buy from the store, so your D-Link needs to be set to DHCP.

 

As well, if you truly don't need a static IP, you should make sure the charge for it gets taken off of your bill (it's somwhere around ~$10/month)

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Occasional Visitor

Re: Correct router configuration for a DPC3939B in 'Bridge Mode'

I set the DLink router to DHCP and restarted it.

 

And no luck ... it shows I'm connected to the wireless connection but I can't access the internet. I beginning to wonder if some setting (firewall maybe??) got missed while configuring DPC3939B into Bridge Mode.

 

Is there a way to access DPC3939B if its in Bridge Mode? If so, which settings should I check for?

 

Thanks!

View solution in original post

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Community Manager
Community Manager

Re: Correct router configuration for a DPC3939B in 'Bridge Mode'

Hi Slydell.  When the Cisco DPC 3939B is in operating in <true bridge mode> all router functions are disabled.  This includes LAN DHCP which is required WiFi functionality.  If your Cisco device is in <true bridge mode> it will only function with one device connected, your router, and all other connections including any wireless access becomes a function of your router.

 

Thank You

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Re: Correct router configuration for a DPC3939B in 'Bridge Mode'

Hi Comcast_John,

 

Would you be able to connect to my Cisco DPC 3939B to check and make sure it's correctly configured and operating in <true bridge mode>?

 

After your confirmation, I'll reconnect my DLink router to the DPC 3939B and test for internet connectivity.

 

Thanks!

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Community Manager
Community Manager

Re: Correct router configuration for a DPC3939B in 'Bridge Mode'

Hi Slydell.  Please send me a private message with WAN/RF MAC Address of the Cisco Device will check the configuration.

 

Thank You

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Community Manager
Community Manager

Re: Correct router configuration for a DPC3939B in 'Bridge Mode'

HI Slydell.  Thank you for the info.  The device is operating in true bridge mode and all router functions are disabled. With the WAN interface of your router set to "obtain IP address automatically (DHCP) it should obtain the public IP address from the Cisco.  Can you access the Internet with a device connected to the D-Link via an Ethernet port on the D-Link router?

 

View solution in original post

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Re: Correct router configuration for a DPC3939B in 'Bridge Mode'

I can not access the internet via Ethernet connection on the D-Link router (with the router connected to DPC3939B), Comcast_John.

 

If it helps, the Internet LED on D-Link shows orange (meaning the connection is good but the router
cannot connect to the Internet).

 

Do you think it could be the D-Link DHCP DNS settings? Primary DNS is set to 75.75.75.75 (Secondary DNS is 75.75.76.76)

 

Thanks.

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Community Manager
Community Manager

Re: Correct router configuration for a DPC3939B in 'Bridge Mode'

HI Slydell.  Those are the correct DNS settings.  Let us know the results when you connect a PC directly to the Comcast gateway.

 

Thank You

View solution in original post

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Re: Correct router configuration for a DPC3939B in 'Bridge Mode'

Thanks for verifying the DNS settings.

 

When connecting my PC directly to the DPC3939B via Ethernet, I can successfully access the internet.

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Community Manager
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Re: Correct router configuration for a DPC3939B in 'Bridge Mode'

Hi Slydell.  Thank you for the update.  This points to an issue with the D-Link router.  Here is a Link to a D-Link product page that may help with the set-up of your particular device.

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Re: Correct router configuration for a DPC3939B in 'Bridge Mode'

I re-ran the D-Link's internet setup once again, and this time I used D-Link's Internet Connection Setup Wizard (instead of the Manual Internet Connection Setup).

 

And it WORKED!

 

Thanks for all your help, Comcast_John!

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