Changing Primary DNS on LAN Settings brings down my whole internet connection

[ccarlin]

I recently configured a new server which I a moving from a Microsoft DNS server to using Unbound. I have manually modified a couple of machines on my network to use the new DNS and it works fine. As soon as I change the DNS Server (under the LAN tab) to use the new server as the primary (going from 10.1.10.92 to 10.1.10.30) my internet connection goes down on all devices. To be clear this includes any machines that don't even use the DNS settings provided by the router. Not a single machine on my network can connect to the internet at all. This includes pinging Ip addresses directly. Changing the DNS setting back to the original IP brings the connection back on all machines. Also while the connection is down I am still able to ping IP addresses via the Comcast Gateway's administrator/Diagnostic tools and that includes by name. As I really need to retire the old server ASAP any help here as to what the heck is going on would be greatly appreciated. Thanks, Chuck

[Comcast_Phil]

Hi ccarlin.

I would like to assist with your DNS settings. Since making the change within the gateway's admin tool, were you also able to adjust the settings within your personal devices as well to accept the changes? You may need to manually configure your personal devices or they may also need to be rebooted as well. 

[ccarlin]

There are several machines on my network, the main one which I use has hard coded DNS settings on the client side. It has been using the new DNS server for weeks without issue. Also the DNS server itself has hard coded DNS settings using the comcast ones 75.75.75.75 etc. I have not checked whether any other machines successfully retrieved the new DNS settings, but I am not sure how that is relevant as ALL machines go offline and that is regardless of DNS (I can't ping an IP address outside of my network from inside) as soon as the new DNS setting takes effect. I can run another test and have my main machine use the DNS settings distributed by the gateway, but the issue seems like something about the DNS settings seem to kill all routing via the gateway outbound/inbound. Again from the gateway admin/diagnostic tools while the rest of the network appears disconnected from the internet I can still ping and resolve names from the gateway. Let me know if you need any further details about the config being used for the DNS (Which again works for any machine pointed to it manually). Thanks, Chuck

[Comcast_Phil]

I would like to review your gateway. Please private message me your full name, the name of your business, the full service address and the phone number associated with your account.