Re: How is DNS resolution working?

From: Ace Fekay [MVP] (PleaseSubstituteMyActualFirstName&LastNameHere_at_hotmail.com)
Date: 02/26/04 

Date: Thu, 26 Feb 2004 18:40:27 -0500

In news:O3osOZC$DHA.2432@TK2MSFTNGP09.phx.gbl,
Ohaya <Ohaya@NO_SPAM.cox.net> posted their thoughts, then I offered mine

> Ace,
>
> I should've mentioned this. When we did the ping, we used the FQDN
> of the host on the external network (e.g., thehost.whatever.com).
>
> Since we were using the external host's FQDN, would the ping still
> have caused the broadcast to the external network for the name?

No, FQDN pings do NOT use broadcasts.

>
> Or, would it only do this broadcast if we had pinged using the
> hostname (e.g., thehost)?

Yes

>
>
> I just thought about one other aspect about all of this that I'm
> starting to wonder about that might have a bearing on all of this...
>
> This is going to get a bit complicated, so here's what the network
> config looks like:
>
> |
> |
> +---- Machine A ---- Switch ----+----
> | |
> E | Machine B
> x----+ [Domain Controller]
> t |
> |
> +--- ExtDNS
> |
> |
>
> Machine B = Domain Controller (domain name "test.foo.com")
> Machine A = Member (joined to Windows domain "test.foo.com")
>
> ExtDNS = a DNS server on external network, which does DNS for
> "foo.com"
> Ext = a machine on the external network (ExtDNS DNS
> name=ext.test.foo.com)
>
> Machine A's IP address is registered in the ExtDNS DNS server, with
> the name "whatever.test.foo.com".
>
> In other words, if you were on machine "Ext", and pinged
> "whatever.test.foo.com", you would end up pinging the external
> interface of machine A.

That would make sense.

>
> Now, we installed Machine B first, and when we installed Win2K on
> Machine B, we set the machine name as "data" and the domain name as
> "test.foo.com". In other words the FQDN for machine B from the
> internal network is "data.test.foo.com".
>
> I think, based on a thread i posted awhile ago, that we could've
> picked just about anything for the domain name (e.g.,
> joe.whatever.foo), but we just happened to pick "test.foo.com".
>
> We then installed Win2K on Machine A (the member server), and we set
> the machine name as "web", and made it a member of (i.e., we joined
> it to) domain "test.foo.com". In other words, the FQDN for machine A
> from the internal network is "web.test.foo.com".

I'm thinking you are providing both DNS addresses (internal and external) on
the A machine in it's IP properties. Not a good thing. Need to keep it
consistent.

>
> If you look in the DNS server on machine B, you'll see that both
> "web.test.foo.com" and "data.test.foo.com" are registered, and have
> "192.xx.xx.xx" IP addresses.
>
> If you ping "web.test.foo.com" from machine B, it resolves to the
> internal ("192.xx.xx.xx") IP address of machine A.
>
> If you ping "data.test.foo.com" from machine A, it resolves to the IP
> address of machine B.
>
>
> Again, machine B is the Domain Controller, and also has DNS Server
> running on it. Machine A is a member server, joined to the domain
> "test.foo.com" (whose Domain Controller is machine B).
>
> Here's where this is going to begin sounding strange...
>
> It just happens that on the external network, there is a Windows
> domain named "foo.com".
>
> But, remember, our machine A is joined to the domain for which
> machine B is the domain controller, not that other Windows domain
> that is on the external network.
>
>
> I'm probably going to muddle this question, but what I'm wondering is
> if there is something strange going on with the name resolution when
> we ping from machine A because we just happen to pick the name of the
> "internal" Windows domain such that that Windows domain's root
> ("test.com") is the same as the name of the Windows domain on the
> external network???
>
> Jim

Let us see an ipconfig /all from both machines please. 

-- 
Regards,
Ace
Please direct all replies to the newsgroup so all can benefit.
This posting is provided "AS IS" with no warranties.
Ace Fekay, MCSE 2000, MCSE+I, MCSA, MCT, MVP
Microsoft Windows MVP - Active Directory
-- 
=================================

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