However, that computer is currently running a large, poorly written program that has brought its processor to its knees. The moral: browsing has to be very tolerant of servers coming and going. Because nearly every Windows system can serve as a browser, there has to be a way of deciding at any time who will take on the job. This decision-making process is called an election. An election algorithm is built into nearly all Windows operating systems such that they can each agree who is going to be a local master browser and who will be local backup browsers.
An election can be forced at any time. For example, let's assume that the CEO has finished his massage and reboots his server. As the server comes online, it will announce its presence, and an election will take place to see if the PC in the spare parts department should still be the master browser. When an election is performed, each computer broadcasts information about itself via datagrams.
This information includes the following:. These values determine which operating system has seniority and will fulfill the role of the local master browser. Chapter 7 describes the election process in more detail. The architecture developed to achieve this is not elegant and has built-in security problems. While a browsing domain can be integrated with domain security, the election algorithm does not take into consideration which computers become browsers.
Thus it is possible for any computer running a browser service to register itself as participating in the browsing election and after winning being able to change the browse list. Nevertheless, browsing is a key feature of Windows networking, and backward-compatibility requirements will ensure that it is in use for years to come. The Windows password functions in a manner that might be a source of confusion for Unix system administrators.
It is not there to prevent unauthorized users from using the computer. If you don't believe that, try clicking the Cancel button on the password dialog box and see what happens! Instead, the Windows password is used to gain access to a file that contains the Windows Networking and network resource passwords. This file is encrypted using the Windows password as the encryption key. As a security measure, you might want to check for junk.
The first time the network is accessed, Windows attempts to use the Windows password as the Windows Networking password. If this is successful, the user will not be prompted for two separate passwords, and subsequent logins to the Windows system will automatically result in logging on to the Windows network as well, making things much simpler for the user. Shared network resources in the workgroup can also have passwords assigned to them to limit their accessibility. The first time a user attempts to access the resource, she is asked for its password, and a checkbox in the password dialog box gives the user the option to add the password to her password list.
This is the default; if it is accepted, Windows will store the password in the user's. Samba's approach to workgroup authentication is a little different, which is a result of blending the Windows workgroup model with that of the Unix host upon which Samba runs.
This will be discussed further in Chapter 9. The peer-to-peer networking model of workgroups functions fairly well as long as the number of computers on the network is small and there is a close-knit community of users.
However, in larger networks the simplicity of workgroups becomes a limiting factor. Workgroups offer only the most basic level of security, and because each resource can have its own password, it is inconvenient to say the least for users to remember the password for each resource in a large network.
Even if that were not a problem, many people find it frustrating to have to interrupt their creative workflow to enter a shared password into a dialog box every time another network resource is accessed.
To support the needs of larger networks, such as those found in departmental computing environments, Microsoft introduced domains with Windows NT 3. A Windows NT domain is essentially a workgroup of SMB computers that has one addition: a server acting as a domain controller see Figure A domain controller in a Windows NT domain functions much like a Network Information Service NIS server in a Unix network, maintaining a domain-wide database of user and group information, as well as performing related services.
The responsibilities of a domain controller are mainly centered around security, including authentication , the process of granting or denying a user access to the resources of the domain. This is typically done through the use of a username and password. Security identifiers are used to represent objects in the domain, which include but are not limited to users, groups, computers, and processes. The part of the SID starting with the "S" and leading up to the rightmost hyphen identifies a domain.
The number after the rightmost hyphen is called a relative identifier RID and is a unique number within the domain that identifies the user, group, computer, or other object. ACLs supply the same function as "rwx" file permissions that are common in Unix systems. However, ACLs are more versatile. Unix file permissions only set permissions for the owner and group to which the file belongs, and "other," meaning everyone else.
ACL support has been added as a standard feature for some Unix variants and is available as an add-on for others. You've already read about master and backup browsers. Domain controllers are similar in that a domain has a primary domain controller PDC and can have one or more backup domain controllers BDCs as well. BDCs frequently synchronize their SAM data with the PDC so if the need arises, any one of them can immediately begin performing domain-controller services without impacting the clients.
All recent versions of Windows can log on to a domain as clients to access the resources of the domain servers. The systems that are considered members of the domain are a more exclusive class, composed of the PDC and BDCs, as well as domain member servers, which are systems that have joined a domain as members, and are known to the domain controllers by having a computer account in the SAM database.
When a user logs on to a Windows domain by typing in a username and password, a secure challenge and response protocol is invoked between the client computer and a domain controller to verify that the username and password are valid. Then the domain controller sends a SID back to the client, which uses it to create a Security Access Token SAT that is valid only for that system, to be used for further authentication.
This access token has information about the user coded into it, including the username, the group, and the rights the user has within the domain. At this point, the user is logged on to the domain. Subsequently, when the client attempts to access a shared resource within the domain, the client system enters into a secure challenge and response exchange with the server of the resource.
The server then enters into another secure challenge and response conversation with a domain controller to check that the client is valid. What actually happens is that the server uses information it gets from the client to pretend to be the client and authenticate itself with the domain controller. If the domain controller validates the credentials, it sends an SID back to the server, which uses the SID to create its own SAT for the client to enable access to its local resources on the client's behalf.
At this point, the client is authenticated for resources on the server and is allowed to access them. The server then uses the SID in the access token to determine what permissions the client has to use and modify the requested resource by comparing them to entries in the ACL of the resource.
Although this method of authentication might seem overly complicated, it allows clients to authenticate without having plain-text passwords travel through the network, and it is much more difficult to crack than the relatively weak workgroup security we described earlier. In addition, WINS is dynamic: when a client first comes online, it is required to report its hostname, its address, and its workgroup to the local WINS server.
This WINS server will retain the information so long as the client periodically refreshes its WINS registration, which indicates that it's still connected to the network.
Multiple WINS servers can be set to synchronize with each other. This allows entries for computers that come online and go offline in the network to propagate from one WINS server to another.
While in theory this seems efficient, it can quickly become cumbersome if several WINS servers are covering a network. That way, only one authoritative WINS server will have the correct information, instead of several WINS servers continually struggling to synchronize themselves with the most recent changes. Both the primary and any other WINS servers will synchronize their address databases on a periodic basis.
Samba 2. One additional aspect of Windows NT domains not yet supported in Samba 2. The protocol that is followed is called pass-through authentication , in which the user's credentials are passed from the client system in the first domain to the server in the second domain, which consults a domain controller in the first trusted domain to check that the user is valid before granting access to the resource.
Note that in many aspects, the behaviors of a Windows workgroup and a Windows NT domain overlap. Let's update our Windows domain diagram to include both a local master and local backup browser.
The result is shown in Figure The similarity between workgroups and NT domains is not accidental because the concept of Windows domains did not evolve until Windows NT 3. Samba can also function as a domain member server , meaning that it has a computer account in the PDC's account database and is therefore recognized as being part of the domain. A domain member server does not authenticate users logging on to the domain, but still handles security functions such as file permissions for domain users accessing its resources.
We won't go into much detail concerning Active Directory because it is a huge topic. Domains in Active Directory can be organized in a hierarchical tree structure, in which each domain controller operates as a peer, with no distinction between primary and backup controllers as in Windows NT domains. The server editions of Windows can be set up to run Active Directory and support Windows NT domains for backward compatibility mixed mode.
In this case, Samba 2. When set up to operate in native mode, Windows servers support only Active Directory. Even so, Samba 2. However, it is not possible for Samba 2. If you want to know more about Active Directory, we encourage you to obtain a copy of the O'Reilly book, Windows Active Directory.
Yes, but most people who have done it have had their share of headaches. Spanning multiple subnets was not part of the initial design of Windows NT 3. As a result, a Windows domain that spans two or more subnets is, in reality, the "gluing" together of two or more workgroups that share an identical name.
The good news is that you can still use a PDC to control authentication across each subnet. The bad news is that things are not as simple with browsing. As mentioned previously, each subnet must have its own local master browser. When a Windows domain spans multiple subnets, a system administrator will have to assign one of the computers as the domain master browser. The domain master browser will keep a browse list for the entire Windows domain. This browse list is created by periodically synchronizing the browse lists of each local master browser with the browse list of the domain master browser.
After the synchronization, the local master browser and the domain master browser should contain identical entries. See Figure for an illustration. If it exists, a PDC always plays the role of the domain master browser. Each subnet's local master browser continues to maintain the browse list for its subnet, for which it becomes authoritative. So if a computer wants to see a list of servers within its own subnet, the local master browser of that subnet will be queried.
If a computer wants to see a list of servers outside the subnet, it can still go only as far as the local master browser. This works because at appointed intervals, the authoritative browse list of a subnet's local master browser is synchronized with the domain master browser, which is synchronized with the local master browser of the other subnets in the domain.
This is called browse list propagation. Samba can act as a domain master browser in a Windows NT domain, or it can act as a local master browser for a subnet, synchronizing its browse list with the domain master browser.
In Version 2. In addition, Samba 2. This functionality has been extended in Release 2. Thus, it is possible to have a Samba server supporting domain logons for a network of Windows clients, including the most recent releases from Microsoft. This can result in a very stable, high-performance, and more secure network, and gives you the added benefit of not having to purchase per-seat Windows CALs from Microsoft. Microsoft Dfs allows shared resources that are dispersed among a number of servers in the network to be gathered together and appear to users as if they all exist in a single directory tree on one server.
This method of organization makes life much simpler for users. Instead of having to browse around the network on a treasure hunt to locate the resource they want to use, they can go directly to the Dfs server and grab what they want.
In Samba 2. Along with this, the Samba team has been adding support for automatically downloading the printer driver from the Samba server while adding a new printer to a Windows client. The list includes Solaris 2. Windows comes with tools that can be used from a client to manage shared resources remotely on a Windows server.
Winbind is a facility that allows users whose account information is stored in a Windows domain database to authenticate on a Unix system. This greatly facilitates account management because administrators no longer need to keep the two systems synchronized, and it is possible for users whose accounts are held in a Windows domain to authenticate when accessing Samba shares. They allow Samba servers to support Unix filesystem attributes, such as links and permissions, when sharing files with other Unix systems.
An advantage of using Samba is that it authenticates individual users, whereas NFS authenticates only clients based on their IP addresses, which is a poor security model. This gives Samba an edge in the area of security, along with its much greater configurability.
See Chapter 5 for information on how to operate Unix systems as Samba clients. We can share a Linux drive with Windows machines. We can access an SMB share with Linux machines. We can share a Linux printer with Windows machines. We can share a Windows printer with Linux machines. In order to install Samba, we will need to log into our Linux server as a user with sudo privileges, or as the root user. To simplify the steps in this tutorial, we will use the root user.
Installation of Samba on CentOS 7. Installed: samba. Configuring Samba. Run 'testparm' to verify the config is correct after you modified it. Other ports:. Now, reload the firewalld service. Configuring Samba for Private Shares. See smb. About the Author: Isabel Kettnich. Common Fixes Featured Articles Getting Started Other Products Cloud Sites 7. Managed WooCommerce Hosting Managed WordPress More and more IOS developers continue to enter the peak of job hopping in Three main trends of interview in IOS bottom layer, algorithm, data structure and audio and video development Occupied the main battlefield.
Data structure and algorithm interview, especially figure, has become the main reason for the failure of most first-line […]. Configuring printers over Samba is similarly easy in both these desktop environments. You will be prompted for your password.
You will be prompted for a user name and password on your Samba server. Identify your Host and Printer on the Samba server and then move on to the next screen. Select your printer model and then click Apply.
To do the same in KDE, open the configuration center by launching the command kcontrol. Click Next another time and then Scan to browse for your Samba server. Alternatively, enter the server details manually. On the next screen, select your printer model from the list. Click through the next few screens and give your networked printer a title to finish up.
A quick trick borrowed from that document for testing your Samba configuration file for obvious errors is to run the following command:. We have only explored basic Samba functionality here, tailored for a home network. More extreme usage scenarios are addressed in detail in the Samba by example guide. About Us. Sign in. Forgot your password? Get help. Password recovery.
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