DNS query basics

Hello
I'm reading on name resolution and experimenting along the way.
My configuration in question is :
1. XP computer DHCP
2. Windows Vista computer DHCP, netBIOS disabled
Both computers get their address from simple hardware router via DHCP.

So as i read name resolution in order on Vista machine goes like this:
a) DNS;
b) LLMNR (not in our case, because xp without IPv6)
c) netBIOS (off on vista, because of experiment)

I suppose in my scenario DNS should be used to resolve names. There is no
primary DNS suffix on ipconfig /all output.
if i ping XP by name (without trailing dot) - it does not respond;
if i use nslookup - it returns the ip address
if i ping xp by name with a trailing dot - it responds.

What kind of DNS query does a resolver do if a machine does not have a
primary DNS suffix and query is made NOT by FQDN, but just a simple name.
Did my query go to the root dns servers and then got lost in the first ping
(without trailing dot)?

Regards,
Valdas

IIRC, if you don't provide a FQDN and the client doesn't have a domain name
then your client wouldn't ship it off to a dns server, since the dns server
wouldn't know what to do with it.

If your client knew of a netbios name server (WINS server) it would send
this query to this server and if that wasn't available or couldn't find it,
it would broadcast the query on the local sub-net. After that it just quits
and comes back with a name not found.

--
Paul Bergson
MVP - Directory Services
MCTS, MCT, MCSE, MCSA, Security+, BS CSci
2008, 2003, 2000 (Early Achiever), NT4
Microsoft's Thrive IT Pro of the Month - June 2009

http://www.pbbergs.com

Please no e-mails, any questions should be posted in the NewsGroup This
posting is provided "AS IS" with no warranties, and confers no rights.

"Valdas Adomaitis" <> wrote in message
news:B7A128FF-FE81-4C8E-BA6A-...
> Hello
> I'm reading on name resolution and experimenting along the way.
> My configuration in question is :
> 1. XP computer DHCP
> 2. Windows Vista computer DHCP, netBIOS disabled
> Both computers get their address from simple hardware router via DHCP.
>
> So as i read name resolution in order on Vista machine goes like this:
> a) DNS;
> b) LLMNR (not in our case, because xp without IPv6)
> c) netBIOS (off on vista, because of experiment)
>
> I suppose in my scenario DNS should be used to resolve names. There is no
> primary DNS suffix on ipconfig /all output.
> if i ping XP by name (without trailing dot) - it does not respond;
> if i use nslookup - it returns the ip address
> if i ping xp by name with a trailing dot - it responds.
>
> What kind of DNS query does a resolver do if a machine does not have a
> primary DNS suffix and query is made NOT by FQDN, but just a simple name.
> Did my query go to the root dns servers and then got lost in the first
> ping
> (without trailing dot)?
>
> Regards,
> Valdas
>
>
>
>
>

"Valdas Adomaitis" <> wrote in message
news:B7A128FF-FE81-4C8E-BA6A-...
> Hello
> I'm reading on name resolution and experimenting along the way.
> My configuration in question is :
> 1. XP computer DHCP
> 2. Windows Vista computer DHCP, netBIOS disabled
> Both computers get their address from simple hardware router via DHCP.
>
> So as i read name resolution in order on Vista machine goes like this:
> a) DNS;
> b) LLMNR (not in our case, because xp without IPv6)
> c) netBIOS (off on vista, because of experiment)
>
> I suppose in my scenario DNS should be used to resolve names. There is no
> primary DNS suffix on ipconfig /all output.
> if i ping XP by name (without trailing dot) - it does not respond;
> if i use nslookup - it returns the ip address
> if i ping xp by name with a trailing dot - it responds.
>
> What kind of DNS query does a resolver do if a machine does not have a
> primary DNS suffix and query is made NOT by FQDN, but just a simple name.
> Did my query go to the root dns servers and then got lost in the first
> ping
> (without trailing dot)?
>
> Regards,
> Valdas

In addition to Paul's response, even if NetBIOS is disabled, in an AD
infrastructure (where the machine is joined with the AD domain name as the
Primary and Search suffix), it will use DirectSMB to resolve it.

If not, such as in your scenario, Paul pretty much covered it. Without the
trailing dot, it is using NetBIOS, but since NetBIOS is disabled, it will
not resolve it, even if in an LMHosts file.

The trailing dot forces the client side resolver to treat it as a hostname
query. However you stated nslookup was able to resolve the host with a
trailing period. What DNS server was it using? Remember, nslookup is a
nameserver lookup tool. If it is set to the ISP's DNS (you didn't state
specifics such as an ipconfig /all of both machines, but I assuming such
since you have a 'simple' network and also assuming no AD is in the
picture), then I can't see how it resolved it, whether hostname, DirectSMB
or lmhosts.

Please read the following regarding nslookup and the client side resolver
algorith.

Microsoft Technet: Nslookup
http://technet.microsoft.com/en-us/l.../cc940085.aspx

Read the following for more info.

http://www.tech-archive.net/Archive/.../msg00611.html
http://www.tech-archive.net/Archive/...4-05/0871.html

[DOC] Using NSlookupFile Format: Microsoft Word - View as HTML
If you fail to fully qualify a name query (that is, use trailing dot), ...
to be a host name and an attempt is made to resolve it using the default
server. ...
http://mcse.villanova.edu/Courses/68...20NSlookup.doc


--
Ace

This posting is provided "AS-IS" with no warranties or guarantees and
confers no rights.

Please reply back to the newsgroup or forum for collaboration benefit among
responding engineers, and to help others benefit from your resolution.

Ace Fekay, MCT, MCITP EA, MCTS Windows 2008 & Exchange 2007, MCSE & MCSA
2003/2000, MCSA Messaging 2003
Microsoft Certified Trainer

For urgent issues, please contact Microsoft PSS directly. Please check
http://support.microsoft.com for regional support phone numbers.

Thank you guys, this pretty much covers all my blind spots.

"Ace Fekay [MCT]" wrote:

> "Valdas Adomaitis" <> wrote in message
> news:B7A128FF-FE81-4C8E-BA6A-...
> > Hello
> > I'm reading on name resolution and experimenting along the way.
> > My configuration in question is :
> > 1. XP computer DHCP
> > 2. Windows Vista computer DHCP, netBIOS disabled
> > Both computers get their address from simple hardware router via DHCP.
> >
> > So as i read name resolution in order on Vista machine goes like this:
> > a) DNS;
> > b) LLMNR (not in our case, because xp without IPv6)
> > c) netBIOS (off on vista, because of experiment)
> >
> > I suppose in my scenario DNS should be used to resolve names. There is no
> > primary DNS suffix on ipconfig /all output.
> > if i ping XP by name (without trailing dot) - it does not respond;
> > if i use nslookup - it returns the ip address
> > if i ping xp by name with a trailing dot - it responds.
> >
> > What kind of DNS query does a resolver do if a machine does not have a
> > primary DNS suffix and query is made NOT by FQDN, but just a simple name.
> > Did my query go to the root dns servers and then got lost in the first
> > ping
> > (without trailing dot)?
> >
> > Regards,
> > Valdas
>
> In addition to Paul's response, even if NetBIOS is disabled, in an AD
> infrastructure (where the machine is joined with the AD domain name as the
> Primary and Search suffix), it will use DirectSMB to resolve it.
>
> If not, such as in your scenario, Paul pretty much covered it. Without the
> trailing dot, it is using NetBIOS, but since NetBIOS is disabled, it will
> not resolve it, even if in an LMHosts file.
>
> The trailing dot forces the client side resolver to treat it as a hostname
> query. However you stated nslookup was able to resolve the host with a
> trailing period. What DNS server was it using? Remember, nslookup is a
> nameserver lookup tool. If it is set to the ISP's DNS (you didn't state
> specifics such as an ipconfig /all of both machines, but I assuming such
> since you have a 'simple' network and also assuming no AD is in the
> picture), then I can't see how it resolved it, whether hostname, DirectSMB
> or lmhosts.
>
> Please read the following regarding nslookup and the client side resolver
> algorith.
>
> Microsoft Technet: Nslookup
> http://technet.microsoft.com/en-us/l.../cc940085.aspx
>
> Read the following for more info.
>
> http://www.tech-archive.net/Archive/.../msg00611.html
> http://www.tech-archive.net/Archive/...4-05/0871.html
>
> [DOC] Using NSlookupFile Format: Microsoft Word - View as HTML
> If you fail to fully qualify a name query (that is, use trailing dot), ...
> to be a host name and an attempt is made to resolve it using the default
> server. ...
> http://mcse.villanova.edu/Courses/68...20NSlookup.doc
>
>
> --
> Ace
>
> This posting is provided "AS-IS" with no warranties or guarantees and
> confers no rights.
>
> Please reply back to the newsgroup or forum for collaboration benefit among
> responding engineers, and to help others benefit from your resolution.
>
> Ace Fekay, MCT, MCITP EA, MCTS Windows 2008 & Exchange 2007, MCSE & MCSA
> 2003/2000, MCSA Messaging 2003
> Microsoft Certified Trainer
>
> For urgent issues, please contact Microsoft PSS directly. Please check
> http://support.microsoft.com for regional support phone numbers.
>
>
> .
>