Server 2003 DNS = 127.0.0.1, any ideas why?

[TechCarnivore]

Hello,
We've just started working with a new customer and one of the many things that struck me as odd is under the network card properties, I see the Server 2003 DNS server listed as 127.0.0.1 as opposed to it's own LAN IP.

I don't see this server doing anything out of the ordinary. File Server, RRAS, DNS.
Can anyone enlighten me as to why someone would configure a server this way?

 

[kmcferrin]

It sounds like you're saying that the server is using 127.0.0.1 for it's DNS server, and that it is running DNS. If that is the case then that shouldn't be a problem, since 127.0.0.1 loops back to the local host. They could have just as easily put in their own local IP address and gotten the same effect with less confusion.

As to why someone would do that, maybe they wanted to make it obvious that it was using itself as a DNS server instead of a different server. If there were multiple DNS servers in their environment at one point then they might have wanted something that made it immediately obvious to anyone that it was handling its own DNS lookups. But technically it makes no difference if a DNS server references itself.

 

[porkchopexpress]

As far as i'm aware that is not the correct way and i've certainly never configured a DC that way.

http://support.microsoft.com/kb/323380

 

[TechCarnivore]

I haven't seen this either, but I'm probably inexperienced when compared to most Tek Tips forum users, which is precisley why I've posed the question here.

I understand that 127.0.0.1 is the loopback IP, but never having seen a server configured this way I thought perhaps I was missing out on some new or cool way to set up a server.

 

[porkchopexpress]

It probably doesn't create any problems but i am aware that the loopback adapter doesn't support certain functions like speed negotiation (not necessary for DNS) and i seem to remember reading somewhere that the loopback adapter wasn't supposed to be used for DNS but i could be remembering this wrong.

 

[itsp1965]

From what I have seen when configuring the first AD DC and installing DNS on it, it seems to use the loopback address as its DNS server IP address. This is to "guarantee" that it doesn't lose its ability to act as a DC since 127.0.0.1 is guaranteed to always be a localhost's IP address whereas another IP address is not. I guess this is used for resiliency sake. There is nothing wrong with using the loopback address in this case