Netbios name and Dns resolution
we have a samba server in the network, its Netbios name is Serversmb, and IP :10.10.10.10
in windows DNS we have an A record Compsamba pointing to the same samba server 10.10.10.10
there is a share in the samba server that I can access from some windows computers but not from few of them if I use DNS name.
For instance:
if I use \\serversmb\sharename I can access the share (serversmb is netbios name)
if I use \\10.10.10.10\sharename I can access the share
But if I use \\Compsamba\sharename, I can't access the share (Compsamba is the dns name for samba server)
I receive the message:
<<\\Compsamba\sharename refers to a location that is unavailable. It could be on a hard drive on this computer, or ona network.Check to make sure that the disk is properly inserted, or that you are connected to the internet or your network, and then try again. If still cannot be located, the information might have been moved to a different location.>>
This happens only from a few windows servers, and don't want to reboot them since they are production servers.
I run the ipconfig /flushdns and didn't help
any idea?
Thanks
This Question has been solved and asker verified All Experts Exchange premium technology solutions are available to subscription members.
Experts Exchange has been collecting answers to technology questions since 1996…3 million and counting! If you have a question, chances are we already have your answer.
If you can't find the exact answer you're looking for, ask our exclusive community of 50,000 experts. You’ll get a personalized answer from a trusted professional.
Thousands of free tech tips, tricks, how-to’s and tutorials are available in our peer reviewed articles section. See for yourself how smart our experts are, no login required.
Save solutions to your questions, answers you’ve discovered through searching plus helpful articles in your personal knowledgebase for easy future access.
Access the answers to your technology questions today.
30-day free trial. Register in 60 seconds.
Members of the expert community talk about why the experience at Experts Exchange is different than what you will find anywhere else.
Try it out and discover for yourself.
30-day free trial. Register in 60 seconds.
Join the community of experts here and help other tech pros by answering question in your area of expertise. You can earn FREE access to all Experts Exchange's premium features and resources.
I don't understand Domain Browse List well enough to answer that. You may want to check out http://support.microsoft.c
From past experience, any number of things can affect the local (computer) and domain browse list:
computer discovery service
netbios
wins service
workgroup
# of computers in a workgroup
using FQDN works just fine for the windows servers that had the issue.
I wonder what's going on with some computers they can open the share by using: \\Compsamba\sharename and some have to use \\Compsamba.domainname.com
where can I find the sourec of the issue?
You can view the Browse List by going to My Network Places -> Entire Network -> Microsoft Windows Network -> <your_domain>
There is a tool called browstat.exe (which is included in the windows tools service pack).
C:\Documents and Settings\Administrator>brow
You can see which PDC and BDC a particular host is using to retrieve the list of computers.
For the hosts the does not work, try setting it to the same PDC as the ones that DO work if possible.
Keep in mind that browse list works via broadcast packets. So if your machines are on different subnets (or vlan, as some vlan configuration do not allow broadcast to pass through even if they are on the same subnet), then there is no way for it to show up on the domain browse list.
OK, I've read the original question and the responses... there appears to be a basic misunderstanding of how both the NetBIOS name lookup and DNS lookups work.
NetBIOS:
======
In NetBIOS, you belong to a "workgroup" (or, potentially, a domain) and any hostname you lookup will FIRST be looked for in YOUR workgroup (or domain). If the hostname is not found immediately (by asking the Master Browser for the workgroup), then a NetBIOS broadcast is performed asking for that hostname to identify itself. This allows systems from OTHER workgroups (or Domains) to be accessed by name, even if they're not "registered" with the Master Browser. (Clients can be configured NOT to answer those broadcast requests, and NOT to register with the Master Browser so as to become "stealth" systems, if they so choose.)
By default, in Window when you type in a URL with \\'s, the assumption is that you are using a NetBIOS name, and therefore ONLY if the NetBIOS lookup fails will it (potentially) consult DNS.
DNS:
===
DNS was created before Windows even had a TCP/IP network stack installed. It was not designed for "workgroup" computers ("workgroups" were supposed to be maintained through the use of local "hosts" files, or possibly Yellow Pages -- later renamed NIS).
Systems that use DNS lookup FQDNs (that is, the host.domainname(s).TLD), unless a default domain has been defined (in Linux, these settings are in /etc/resolv.conf - In Windows, they are in the advanced TCP/IP IPv4 settings of your network connection -- the field marked "Append <whatever> to DNS suffix").
Together (from a Windows client system):
==========================
So, if I lookup "\\serversmb", I'll ask the Master Browser for the address -- and you're getting one quickly.
If I lookup "\\10.10.10.10", I don't have to look anything up -- I get the server address and connect quickly
But, if I lookup "\\compsamba", I check NetBIOS (and fail), then check DNS -- and if there is no "default domain" set, then DNS also fails. The delay you'll encounter comes from the NetBIOS waiting for the "results" of its broadcast for hosts named "compsamba").
So, in this case, it appears that your Windows system doesn't know to use your local DNS domain to look for the system compsamba. So, if your local DNS server is at 10.10.10.100, and your local domain is called localdomain.local (such that a query at 10.10.10.100 for Compsamba.localdomain.loca
I hope this helps!
Dan
IT4SOHO
No, it is the former -- the Microsoft "Computer Name" is the NetBios name. That's one of the issues with NetBios over DNS -- in NetBios, the local (host) user with local (host) admin rights can change his name of his system on the LAN. Under DNS, the name is assigned by a server (the DNS server).
Then again, under NetBios, when you get a new/different DHCP address, there are no changes that need to be made (the NetBios Master Browser will update automatically), where in DNS there has to be a DHCP-to-DNS update that many admins consider a security risk.
Dan
IT4SOHO
Let's make this clear:
1) Hostname and DNS name are NOT related... Hostname and NetBIOS name ARE related.
1a) DNS names are assigned by a central database server, and the "client" system has no way to alter it
1b) NetBIOS names are self-assigned and "reported" to the "Browser Master" (server) -- so a client system who changes its name may appear to be a totally different system on the LAN
2) Changing the hostname WILL require re-establishing your NetBIOS network connections, but not your TCP/IP or DNS relationships.
2a) Changing the Hostname on a Windows system WILL change the NetBIOS name, and it WILL require that the system reboot. It will NOT require Windows to be re-installed.
2b) Changing the Hostname on a Linux system does NOT affect the NetBIOS name (THAT is set in the smb.conf file), does NOT require a reboot (although changing the NetBIOS name in smb.conf DOES require restarting Samba), and obviously won't require re-installing Linux.
I hope this helps to clear up any confusion...
Dan
IT4SOHO
if I type hostname at the command prompt I will get the same name as if going to computer/properties/comput
The computer name assigned at the computer name tab will be created as a record in the DNS when the computer is joined to the domain.
I can change the hostname by going to computer/properties/comput
so when does the netbios name of the computer gets created.
and how to change it and how to display the netbios name of the computer?
- The hostname on the Windows system has NOTHING TO DO with DNS. Any correlation is purely "accidental" (albeit, quite possibly intentional).
- DNS names come from a DNS server. It is POSSIBLE that the DNS server is accepting updates from a DHCP server, so that when a system gets a new IP address, the DNS server is updated -- but this too has NOTHING to do with the system's machine name.
- In Windows, the netbios name *IS* the system's hostname. When the system boots, it "announces" itself to the "workgroup" that it is configured to be on (this is done with a broadcast message). Somewhere out on the LAN there will be a Master Browser (just another system, Windows, Linux, Mac, or otherwise) who will reply -- thus informing the Windows Client who the Master Browser is for future name (WINS) lookups. If no one answers, the Windows client will BECOME a Master Browser for the workgroup. Also, some client systems will, immediately upon connecting to a Master Browser, "force an election" to choose a NEW Master Browser -- after all, with the addition of a new system, the topology of the LAN has changed -- and perhaps that change is significant.
So, if my Windows client has a hostname (from the system properties control panel) of SYSTEM, when it boots up, it will send a BROADCAST message (IP address 255.255.255.255) asking for a DHCP server.
- That server will reply with an address (say, 10.0.0.10)
- It is possible that the DHCP server has a configured name for that client, or that it will take the self-reported name of the client, and it MAY send an update to the DNS server
- In modern times, it will be AFTER this receipt of the DHCP response (or failure to respond - in which case, the system will self-assign itself a 169.254.x.x address) that the Windows Client will then do a network broadcast (in this example, sent to 10.0.0.255) announcing its name and workgroup, and requesting the location of the Master Browser for that workgroup.
DNS names are resolved by a DNS server, set in your TCP/IP settings (maybe manually, maybe by DHCP) -- usually listening on UDP port 53.
NetBIOS names are resolved by the Master Browser (which you have NO control over the selection or election of).
So, in answer to each of your questions:
- If you type hostname at a DOS window prompt, you will get the hostname AND the NetBIOS name of the system, as they are one and the same. What you won't have is the workgroup name. To get all of it together, use the command "net config workstation"
- When a system joins a domain, it creates a named entry (that is its hostname) within the domain controller -- but not necessarily a DNS entry. Again, the process of making a DNS entry MAY be automated, but it is not automatically done. However, the joining of the system to the Domain DOES make the NetBIOS entry in the Domain Server (whether PDC/BDC or AD).
- If you change the hostmame in the system properties control panel, you will corrupt your entry in the Domain Server's tables -- in other words, you will need to re-join the domain. (Although I think AD servers can handle this better than PDC/BDC servers). The name change will not take effect until reboot in any case. Again, if DNS entries are automatically changed it is because someone configured an automated update, NOT because it is normally automatic.
- The NetBIOS name of the computer is "created" from the hostname of the computer at boot time. When the system shuts down, the NetBIOS name "disappears" from the Master Browser's list (yes, after some timeout -- there is no specific communication "announcing" a shutdown).
- Display the NetBIOS name of the system with the DOS command "net config workstation"
I hope this helps!
Dan
IT4SOHO
<<net config workstation>>
This will show the computer name as it is showing up in DNS server or in computer/properties/Comput
What I think is the first Netbios name of te computer gets it when you install the OS, then when you change it in the computer/properties /computer name, it will change automatically in the netbios name.
I apologize -- I have written this down twice already, and somehow you aren't able to understand it.... I will see if a third time does the trick, but this is as far as I go on this question....
During the Windows installation process, you are FORCED to provide a machine name, although with some installations it offers a suggestion that uses the personal name you provided earlier in the installation process with some random characters after it. (like dan-we419s0a). You CANNOT leave this blank. Later in the installation process, the system must reboot -- if for no other reason than to install the system name... WHICH IS ALSO YOUR NETBIOS NAME.
SYSTEM NAME <=--=> NetBIOS NAME : THEY ARE THE SAME THING!
- Any "local" administrator (member of the machine's Administrators group -- and in a Domain environment, that also includes the Domain Admins group) can CHANGE the NetBIOS name by simply changing the machine name and rebooting.
THERE IS NO (repeat: NO) WAY to change the NetBIOS name of a Windows system without changing the system name and rebooting.
If your hardware is connected to a network (that is, if the network driver was pre-loaded and you are connected already), the system will give you an ERROR if there is another system on the network with the same name. If you boot a windows system onto a network and it detects another system with the same name, BOTH are supposed to warn you that another system with the same name is on the LAN, and the "new" one is supposed to DISCONNECT from the NetBIOS (workgroup) network. (The error message usually doesn't tell you how to fix it -- change the name of your computer & reboot!)
If, when you type "net config workstation" it shows you your DNS name, it is only BY ACCIDENT that your NetBIOS name and DNS name are the same. DNS and NetBIOS have NO RELATION to each other. Changing one does NOT affect the other. They can be the same, they can be different -- both are legal and fine in many circumstances.
BTW: In the output of the "net config workstation", MOST of the references to "DOMAIN" are actually references to "WORKGROUP" (or PDC/BDC Domain or AD domain) -- NOT a DNS domain.
Just as it is legal (possibly desirable) to have your NetBIOS name match your DNS name, it is often the case that your NetBIOS Domain (Workgroup, PDC/BDC, or AD) will match your DNS name. That is another topic, but IMHO it is "bad form" to make them exact. Personally, I make my AD domain "mycompany" and my local DNS domain "mycompany.local" just so I know the difference.
===
So, now you know how to find your own NetBIOS name -- so maybe you want to find out your DNS name?
Well, that can be MUCH harder -- because DNS names are controlled by the DNS server, which you may or may not have access to. One thing you CAN do however is find out if there is a REVERSE DNS record for your IP address, and this SHOULD (if DNS was configured completely & properly) give you at least one DNS name by which you can be called. (You see, DNS can give your computer MANY names -- NetBIOS is a one-to-one relationship in that you can have only one NetBIOS name).
To see if you have a REVERSE DNS entry for your system, do the following:
1) Get your IP Address:
ipconfig
NOTE: It SHOULD be a 192.168, 172.16-31, or 10. address -- anything else is potentially an Internet Address, except 169.254 addresses, which are "DHCP failure" addresses.
2) Query for your reverse DNS entry (I will assume your IP address ia 192.168.0.100):
nslookup 192.168.0.100
NOTE: If you get an error message it just means your DNS server isn't maintaining the reverse mappings. Not optimal or complete, but still usable. Unfortunately, it DOES mean that you'll have no definitive way of seeing what your DNS name(s) might be on your DNS domain
I hope this answers your questions...
Dan
IT4SOHO
Business Accounts
Answer for Membership
by: oocytePosted on 2009-10-19 at 14:58:36ID: 25609401
\\ uses Domain Browse List (LM names) by default.
If you want to access \\Compsamba, you need to provide the fully qualified domain name, eg:
\\Compsamba.yourdomain.com
You do not need a reboot, a quick fix would be putting an entry for compsamba in your
c:\windows\system32\driver
Networks -> LAN Properties -> TCP /IPv4 -> Properties -> Advanced -> WINS
Enabled LMHOSTS lookup and Import the LMHOSTS file you created.