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New Member

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3 Messages

Sun, Sep 26, 2021 11:33 PM

Multiple Dynamic IPs in Bridge Mode

I have a Comcast Business account and placed my modem in bridge mode. From the modem, I currently have three routers connected, each pulling different WAN IPs via DHCP (assuming dynamic since I don't have any static IPs in my account).

I was wondering what the specifications are for these IP addresses. How many dynamic IP addresses could be pulled by a single modem when connecting routers to ports on a bridged modem?

Official Employee

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9 Messages

1 m ago

Hi, @GARDEN. Thank you for reaching out. I'd like some more clarification regarding your set-up. The Bridge Mode option for our equipment can disable the additional ports most times. Are you currently using an Xfinity Gateway in Bridge Modem with multiple routers, or did you purchase your own equipment? The modem will provide 1 Dynamic IP address. From there, the routers will take over. 

New Member

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3 Messages

@Comcast_Vianney Yes I have the usual Comcast Business Wireless Gateway in Bridge mode. I have three routers connected directly to the modem, and all three are pulling dynamic IPs as WAN.

It was intended to be just in the interim while I moved the router in between the modem and rest of the network, but I wanted to know what the specs are on a behavior like this. Is there a limit to the number of Dynamic IP addresses provided?

Official Employee

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37 Messages

Thank you so much for that information! Here is a link with more information about using the Dynamic IP versus our Static IP, https://comca.st/3AON2eR. Let me know if this information is helpful or if you have any additional questions! We are here to help! 

New Member

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3 Messages

@Comcast_Jeniece

So I read through the link, and it doesn't have any information on how many Dynamic IP addresses my modem can pull simultaneously via DHCP. For example, if I were to connect 10 different routers directly to a bridged modem, would all 10 routers get different dynamic IP addresses assigned via DHCP? That's the case right now for my 3 routers, but I haven't tested it further.

Official Employee

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5 Messages

In theory, every router connected should be assigned its own dynamic IP address. However, this would depend on how many devices are connected. Your gateway's IP address is used to determine the DHCP range for your local network. One of two things can occur if you connect more devices than your gateways IP address allows. The additional device would either not be assigned an IP address or it would receive a duplicate IP address within the range, which could lead to connection issues. Unfortunately, after reviewing the manual for the modem, I am not seeing the exact number of IP addresses that would be provided within the range.