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The Graveyard - Products No Longer Supported => Routers / COVR => DIR-825 => Topic started by: stephenkca on September 08, 2009, 11:54:27 AM

Title: How to disable DHCP connection-specific DNS suffix?
Post by: stephenkca on September 08, 2009, 11:54:27 AM

DIR-825, Hardware Version A1, Firmware Version 1.12NA

I just updated the firmware from version 1.01.

When my XP-based laptop connects now, the connection-specific DNS suffix is set to something apparently given to the router by the WAN.  (I say "apparently" because clearly it comes from my ISP but I don't see it on the status screen for the router.)  Previously it was left blank.

Is there any place in this firmware version to tell DHCP not to provide the connection-specific DNS suffix?  I've experimented in Network Settings, but haven't been able to make this happen.  I can set Local Domain Name and have that replace the WAN-provided name, but I can't set the name to blank. 

I know there are various workarounds (set a local domain name and use that, set specific names in hosts), but I'd prefer not to have to use them.

Title: Re: How to disable DHCP connection-specific DNS suffix?
Post by: Lycan on September 08, 2009, 03:02:11 PM

Enabling  the DNS relay should solve that.

Title: Re: How to disable DHCP connection-specific DNS suffix?
Post by: stephenkca on September 08, 2009, 03:37:41 PM

Quote from: Lycan on September 08, 2009, 03:02:11 PM

Enabling  the DNS relay should solve that.

DNS relay is enabled.  Or rather, it is grayed out but checked off.

Should the check box be grayed?

Title: Re: How to disable DHCP connection-specific DNS suffix?
Post by: Kanati on September 08, 2009, 04:03:39 PM

Not meaning to jump in front of Lycan on this answer, but I believe "DNS Relay" is checked and grayed out because "Advanced DNS Service" is ENABLED (checked) under the Internet Connection page. In other words...if I uncheck the "Advanced DNS Service" option, I regain control over the "DNS Relay".

Title: Re: How to disable DHCP connection-specific DNS suffix?
Post by: Lycan on September 09, 2009, 08:43:03 AM

Odd,
Whats the DNS suffix your being assigned?

Title: Re: How to disable DHCP connection-specific DNS suffix?
Post by: stephenkca on September 09, 2009, 09:37:53 AM

Quote from: Lycan on September 09, 2009, 08:43:03 AM

Odd,
Whats the DNS suffix your being assigned?

phub.net.cable.rogers.com

My ISP is rogers.com.  Presumably the suffix is assigned by their DHCP to my cable modem and in turn by my cable modem to the router.

Title: Solved the problem
Post by: stephenkca on September 16, 2009, 09:14:42 AM

The problem isn't Enable DNS Relay.  The problem is the Advanced DNS Service.  When I disable it (which is done using Setup > Internet > Manual Internet Connection Setup : uncheck Enable Advanced DNS Service) then the suffix isn't appended to unqualified network requests.  If it is enabled then apparently the router is appending what it thinks is the local domain name to unqualified names.  This means that attempts to access local computers when there is no local domain fail.

(Enable DNS Relay is no longer grayed out when Advanced DNS Service is disabled, BTW, but its enabled status is irrelevant to this problem.) 

For instance, with Advanced DNS Service enabled, if I "ping dev1server" then the ping request goes to dev1server.phub.net.rogers.com.  Similarly, Remote Desktop Sharing fails.  If I disable Advanced DNS Service then the problem goes away.

The Advanced DNS Service code needs to be revisited, or at least this behaviour needs to be documented.