IP Address is Incorrect

Posts: 7 · New Forum Member Joined: Apr 28, 2006 Posts: 7

Equipment:
1. Motorola SB4100 Cable Modem
2. Linksys BEFW1154 Wireless Router IP 192.168.1.1
3 Linksys RTP300 Box provided by Vonage
Cable Provider: Comcast

Connection: 1 to 2 and 3 to 2. Phone is connected to 3.

Problem: When I look at 2, the Internet IP address shown under the Status\Router tab does not reflect the Internet IP address assigned by Comcast to my Cable modem. This neve occured before I got Vonage in January. Any thoughts?

Posts: 476 · Posted: Fri Apr 28, 2006 9:20 pm Post subject:

Are you saying you're supposed to have a static IP from Comcast? If you're not paying for a static IP (does Comcast even offer static IP service?) you're most likely just seeing the IP that was assigned by DHCP. If you can still connect to the internet then there's nothing to be concerned about.

Posts: 7 · New Forum Member Joined: Apr 28, 2006 Posts: 7

It's not a static ip address - but I thought my non Vonage Linksys router was supposed to pick up the ip address as Comcast changes it. I've opened up ports so my DLink web cam can be accessed from the internet - so it is important that my non Vonage Linksys router picks up the current ip address assigned by Comcast.

Posts: 171 · Posted: Sat Apr 29, 2006 8:40 am Post subject:

How do you have the two routers hooked up? If you have the RTP300 plugged into your cable modem, then plug your BEFW1154 into the RTP300, then your BEFW1154 will get an IP address assigned by the RTP300 router's DHCP server.

If you attach the BEFW1154 to the cable modem first, then it will receive a WAN address assigned by Comcast, however the RTP300 will not be able to prioritize the Voip packets and you may degrade the quality of your phone service.

Posts: 7 · New Forum Member Joined: Apr 28, 2006 Posts: 7

I have the If you attach the BEFW1154 to the cable modem first, it does not reflect the latest WAN address assigned by Comcast. It seems to be stuck to the IP address Comcast assigned back in December, when I initiated Vonage service.

Posts: 171 · Posted: Mon May 01, 2006 12:05 pm Post subject:

Try a hard reset (button on back) or do a factory reset from browser. The other alternative is to release the WAN address and request a new one. That's also done through the browser interface.

Posts: 7 · New Forum Member Joined: Apr 28, 2006 Posts: 7

Have done a DHCP release and a DHCP renew. No luck. Router shows an IP address that is not the current IP address Comcast has assigned to my cable modem.

Posts: 476

Robmyaing wrote:

Have done a DHCP release and a DHCP renew. No luck. Router shows an IP address that is not the current IP address Comcast has assigned to my cable modem.

How do you know it's not the IP address that Comcast has assigned to your cable modem? That's the part I don't get. The router gets the external IP from the cable modem. It doesn't just pick one out of thin air. When you do a DHCP release/renew on your router, it's picking up the current IP your cable modem has been assigned. I guess I don't understand why you think this is different than what Comcast has assigned to your cable modem since that is the very place that the router is getting the IP from.

Posts: 7 · New Forum Member Joined: Apr 28, 2006 Posts: 7

I know that the router is not showing the most current Comcast assigned IP address because - 1. It has not changed in months and 2. I connect my computer directly to the Comcast cable modem and run IPCONFIG and also check on the What's My IP web site. IPCONFIG and What's My Ip show the same IP address but the router shows some other IP address.

Posts: 476 · Posted: Mon May 08, 2006 12:03 pm Post subject: Re: Incorrect IP address

Robmyaing wrote:

I know that the router is not showing the most current Comcast assigned IP address because - 1. It has not changed in months and 2. I connect my computer directly to the Comcast cable modem and run IPCONFIG and also check on the What's My IP web site. IPCONFIG and What's My Ip show the same IP address but the router shows some other IP address.

What you mention as point #1 is typical. You may never see the IP change even though it's assigned by DHCP. It might change, but it might not. As for point #2, this is also typical. Different MACs tend to get the same IP assigned to them that they got the last time they were connected directly. You could try cloning your computer's MAC address on your router and see what IP it assigns then. However, is there an issue when the router has the "wrong" IP? Can you not connect to the internet? Or are you running some type of server and people outside can't connect to it? If so, are they using the IP that you see on your router or are they still trying to use the other IP you see when you connect your PC directly to the cable modem?