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[arisia]

Greetings,

Apologies if this has been posted and answered in the past - I did a search of the forums and wasn't able to find this specific piece of information.

I have the DIR-655 (H/w Ver B1, F/W Ver 2.05NA) set up as router on my network (TWC/RR - modem is Motorola SURFBoard 6121 - modem only, no router or other services provided). I have configured the router sufficiently to allow all computers on the local network to access the Internet, and have configured the DHCP server on the router to provide IP addresses to the local network. I have configured the router to provide the DNS addresses for my local DNS resolvers (so that I can provide DNS resolution for an "internal" domain). Configuration specifics available on request, but everything mentioned so far is working satisfactorily, at least so far.

So, my question: The "Local Domain Name" setting on the router, as indicated in the documentation, provides a connection-specific domain name when DHCP supplies an IP address to the local system. This setting, however, is overridden if the ISP provides a domain name when it assigns an IP to the WAN connection. I have verified by experiment that this is true (no matter what I put in the Local Domain Name field - whether a valid domain, or blank - the local machines receive the domain name supplied by the ISP.

I wish to modify this behavior. I wish to have the router provide the domain name specified in the Local Domain Name field *regardless* of what the ISP provides.

Is this possible? And if so, how?

Tracy

[FurryNutz]

You would probably have to contact your ISP and ask them about this. This comes from them and gets assigned by them. I don't think there is any way of preventing it if they are using a name there. Some ISPs do, some don't like mine.

[arisia]

Greetings,

Thank you for your answer. As I understand your answer, you said: if I do not wish the ISP to provide a domain name for the connection, I would need for them to change the configuration on their end.

However, that's not quite what I wanted to know - what I want to know is: is there a way to set the DIR-655 so that it will provide a specified domain name for LAN based computers through DHCP *without regard to* what the ISP may or may not have provided for the WAN connection?

The connection specific domain name doesn't have any relevance outside of my local network - the only real use for it is in providing extended DNS resolution within the network, so that if a user were to type, for example, PING FOO the resolver would first attempt to look up FOO in DNS. If it were unsuccessful in finding FOO, then it would append the connection specific domain name and reattempt DNS lookup.

By providing a locally specified connection specific domain name, I can allow users who don't think about DNS and FQDN names with DNS resolution that will nevertheless still function as expected at the local LAN level. However, if the ISP assigned connection specific domain name is provided by DHCP, local resolution of unqualified domain names becomes "broken", as the FQDN produced when the initial lookup fails is not registered with either the ISP's DNS server, or with my own DNS server.

Examples (fictional names):

Example 1:
ISP provided connection specific domain name: foo.bar.neo.rr.com
DHCP provided connection specific domain name: <echos ISP provided name>

End user attempts to resolve DNS name: quack

NSLOOKUP attempts DNS resolution of FQDN "quack" - fails
NSLOOKUP attempts DNS resolution of FQDN "quack.foo.bar.neo.rr.com" - fails

End result: fail

Example 2:
ISP provided connection specific domain name: foo.bar.neo.rr.com
DHCP provided connection specific domain name: duck.local

End user attempts to resolve DNS name: quack

NSLOOKUP attempts DNS resolution of FQDN "quack" - fails
NSLOOKUP attempts DNS resolution of FQDN "quack.duck.local" - success

End result: success

So what I need to know is - is this possible, using the DHCP setup in the DIR-655? And if so, how?

Thank you for your assistance so far, and also in anticipation of any additional information you can provide.

[FurryNutz]

You may want to try testing with DNS setting manually entered into Setup/Internet/Manual then DNS Relay and Advanced DNS Services OFF.
Also you might want to setup IP reservations on the router for ALL devices.

[FurryNutz]

Any status on this? 

[arisia]

Hi,

Sorry for the long delay on getting back to you - the intervening holiday was a bit more "intrusive" than I had planned.

I do have the DNS settings manually entered (so that name resolution is going through my servers rather than through the ISP servers), and DNS Relay is turned off (else my servers would never be hit). I also tried turning Advanced DNS Services off (and on) - neither seemed to really be of much help in the matter.

I have not set up reservations for all devices on the network. It seems to me that doing this would accomplish no more than would simply assigning "static" IP addresses for the various devices, which is not what I am attempting to accomplish (and would seem to defeat the very purpose of using DHCP, that of assigning IP addresses to devices as needed, rather than simply assigning IP addresses to each device).

So far, my "workaround" has been to simply tell users they cannot use unqualified DNS names. And that works, mostly - although it does break some services.

I would still be interested in finding out if there's a solution to this, but I'm beginning to suspect that there simply isn't. From what I'm seeing here, and in looking through the router manual, and what I can deduce from the router setup, it seems that the firmware coding simply didn't take this possibility into account. Seems a shame, since the router is otherwise a decent router (so far - it's only been a couple of weeks).

Tracy

[FurryNutz]

It seems that the system is working as expected and your ISP is probably the point of control for the local domain. Not sure how or why they are doing this. I would ask your ISP if they have any DNS or Domain name policies. I can enter in a Local Domain Name and MY ISP isn't doing anything with it. I see the name appear in Network Places. I also use other DNS manually aside from default ISP DNS and those are also manually entered in with DNS Relay and Advanced DNS Services OFF.

One reason for using Reserved IP address assignment which does not defeat DHCP IP address assignment is the benefits of help in troubleshooting, avoids conflicts, ease of management and identification of devices on the network, avoids possible feature rule breaking should the IP address change on the device and each device gets it's own IP address each and every time it connects. These are highly recommended reasons for using Reserved IP addressing which the benefits out way most DHCP assignment benefits. However these are at users discretions.

I would phone contact DLink support, say level 2 or higher and present this to them and see how it goes.

Keep us posted and let us know what they say.