My laptop is getting both a valid IP address and the broadcast address on this network
Posted on 2016-11-25
I've had a long standing issue at a client site where there is a Comcast gateway, a couple of Ubiquiti access points and a security system with DVR. When I connect my laptop to this network, I am unable to access the Comcast gateway until I first disconnect the DVR, then reboot the gateway. At that point, I can access the Comcast gateway web GUI at 10.1.10.1. When I reconnect the DVR, I again lose access to the Comcast gateway. The network works fine otherwise. While I lose access to the gateway on the private side of the device, Comcast is able to access it fine from the WAN. I always assumed it was a problem with the DVR. Recently, both the Comcast gateway was replaced because of a dead port and the DVR was replaced because a power surge took it out. I was called out to put the new DVR IP address in the DMZ of the Comcast gateway, which I did. Even after both devices have been replaced, I still have this issue with accessing the web GUI of the Comcast gateway. This time I ran an IP scanner (Advanced IP Scanner from Famatech) and found that my laptop was getting BOTH a valid IP address on the 10.1.10.0/24 subnet AND ALSO the broadcast address at 10.1.10.255. Both addresses are associated with the MAC address of my laptop. I have looked at a lot of networks over the years, but I have never seen a device get the broadcast address for the network. Is this a clue that may be related to the web GUI access issue? Ideas on how to troubleshoot this? Or is this maybe a fluke of the IP scanner?