“UbuntuHelp:ActiveDirectoryWinbindHowto”的版本间的差异

2007年11月22日 (四) 11:58的版本

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https://help.ubuntu.com/community/ActiveDirectoryWinbindHowto

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This Howto describes how to add a Ubuntu box in a Active Directory domain and to authenticate the users with AD.

Used software

Used terms

Confirm Connectivity

The first step to configuring an Ubuntu client for participation in an Active Directory (AD) network is to confirm network connectivity and name resolution for the Active Directory domain controller. An easy way to verify both of these is to ping the fully-qualified domain name (FQDN) of the AD DC on your network.

root@linuxwork:~# ping win2k3.lab.example.com

PING win2k3.lab.example.com (10.0.0.1) 56(84) bytes of data.
64 bytes from win2k3.lab.example.com (10.0.0.1): icmp_seq=1 ttl=128 time=0.176ms

The output of the ping response shows successful resolution of the FQDN to an IP Address, and the confirmation of connectivity between your Ubuntu workstation and the AD DC.

Time settings

Time is essential for Kerberos, which is used for authentication in Active Directory networks. The easiest way to ensure correct time syncronization is to use a NTP-Server. Every Active Directory Domain Controller is also an NTP server, so for best results, use the FQDN of an AD DC in Ubuntu's default ntpdate application, which syncs time at startup or on demand.

For Kubuntu 7.10 (and likely other versions as well) ntpdate does not pull the servername from any config files, instead it expects the NTP server as an argument on the commandline. Therefore it is simplest to work with the options of adjust date and time of the GUI clock. Choose set date and time automatically, and then enter your AD DC as the NTP server. If it is reading from the config files then set things up in /etc/default/ntpdate as below.

file: /etc/default/ntpdate

# servers to check
NTPSERVERS="win2k3.lab.example.com"
# additional options for ntpdate
NTPOPTIONS="-u"

root@linuxwork:~# /etc/init.d/ntpdate restart

* Synchronizing clock to win2k3.lab.example.com...    [ ok ]

FQDN

A valid FQDN is essential for Kerberos and Active Directory. Active Directory is heavily dependent upon DNS, and it is likely that your Active Directory Domain Controllers are also running the Microsoft DNS server package. Here, we will edit the local hosts file on your Ubuntu workstation to make sure that your FQDN is resolvable.

file: /etc/hosts

127.0.0.1 linuxwork.lab.example.com localhost linuxwork

You can test your configurating by PINGING your own FQDN. The output should be similar to the PING output above, from the Network Connectivity test (of course, the FQDN will be your own, and the IP address will be 127.0.0.1).

Set up Kerberos

The first step in setting up Kerberos is to install the appropriate client software.

Required software

To properly install the necessary Kerberos packages, you need to install the krb5-user and libpam-krb5 packages from the Universe Repository.

If you do not intend to acquire a Kerberos ticket at login, you need not install the libpam-krb5 package.

This command will also fetch the additional packages krb5-config, libkrb53, and libkadm55.

The krb5-config installation will present a prompt:

What are the Kerberos servers for your realm?
win2k3.lab.example.com

What is the administrative server for your Kerberos realm?
win2k3.lab.example.com

These prompts should be answered according to the Active Directory Domain Controller in charge of your domain. The krb5-config process customize the /etc/krb5.conf file for your installation. In most cases, this config file will work successfully, but if you want a more streamlined config file (e.g., without all the Kerberos 4 cruft), you can use the following as a template:

file: /etc/krb5.conf

[logging]
default = FILE:/var/log/krb5.log

[libdefaults]
ticket_lifetime = 24000
clock_skew = 300
default_realm = LAB.EXAMPLE.COM
#   dns_lookup_realm = false
#   dns_lookup_kdc = true

[realms]
LAB.EXAMPLE.COM = {
kdc = win2k3.lab.example.com:88
admin_server = win2k3.lab.example.com:464
default_domain = LAB.EXAMPLE.COM
}

[domain_realm]
.lab.example.com = LAB.EXAMPLE.COM
lab.example.com = LAB.EXAMPLE.COM

Notice the two "DNS" directive are commented out. You can elect to use DNS to find Kerberos realm servers, or you can elect to use the krb5.conf file to define Kerberos realm servers. If you elect to use DNS, uncomment the two lines above and instead comment or remove the entire directive for your realm under the [realms] heading.

Testing

Request a Ticket-Granting Ticket (TGT) by issuing the kinit command, as shown (you can use any valid domain account; it doesn't have to be Administrator. You can also omit the domain name from the command if the "default_realm" directive is properly applied in the /etc/krb5.conf file.

root@linuxwork:~# kinit [email protected]
Password for [email protected]: ****

Check if ticket request was valid using the klist command.

root@linuxwork:~# klist
Ticket cache: FILE:/tmp/krb5cc_0
Default principal: [email protected]

Valid starting     Expires            Service principal
01/21/05 10:28:51  01/21/05 20:27:43	krbtgt/[email protected]
renew until 01/21/05 20:28:51

At this point, your Kerberos installation and configuration is operating correctly. You can release your test ticket by issuing the kdestroy command.

Join AD domain

Required software

You need to install the winbind and samba packages. You can also install the smbfs and smbclient packages too.

For Windows 2003 Server SP1 Winbind version 3.0.14a is necessary. In Hoary is only version 3.0.10, but you can find 3.0.14a in Breezy.

The package smbfs is optional, but includes useful client utilities, including the smbmount command. Also useful is the smbclient package, which includes an FTP-like client for SMB shares.

Join

file: /etc/samba/smb.conf

[global]
security = ads
realm = LAB.EXAMPLE.COM
password server = 10.0.0.1
# note that workgroup is the 'short' domain name
workgroup = LAB
#       winbind separator = +
idmap uid = 10000-20000
idmap gid = 10000-20000
winbind enum users = yes
winbind enum groups = yes
template homedir = /home/%D/%U
template shell = /bin/bash
client use spnego = yes
client ntlmv2 auth = yes
encrypt passwords = yes
winbind use default domain = yes
restrict anonymous = 2
# to avoid the workstation from
# trying to become a master browser
# on your windows network add the
# following lines
domain master = no
local master = no
preferred master = no
os level = 0

The "winbind use default domain" parameter is useful in single-domain enterprises and makes winbind assume that all user authentications should be performed in the domain to which winbind is joined. Omit this parameter if your environment includes multiple domains or if your account domain differs from the resource domain. The "winbind separator" directive is optional, and the default value is the usual backslash "\" Domain and User separator. You can use "+" if you know of a specific reason "\" will not work in your environment.

Be sure to restart the Samba and Winbind services after changing the /etc/samba/smb.conf file:

root@linuxwork:~# /etc/init.d/winbind stop
root@linuxwork:~# /etc/init.d/samba restart
root@linuxwork:~# /etc/init.d/winbind start

Request a valid Kerberos TGT for an account using kinit, which is allowed to join a workstation into the AD domain. Now join to the domain, if the ticket was valid you should not need to supply a password - even if prompted you should be able to leave it blank.

root@linuxwork:~# net ads join
Using short domain name – LAB
Joined 'linuxwork' to realm 'LAB.EXAMPLE.COM'

If the Kerberos auth was valid, you should not get asked for a password. However, if you are not working as root and are instead using sudo to perform the necessary tasks, use the command sudo net ads join -U username and supply your password when prompted. Otherwise, you will be asked to authenticate as [email protected] instead of a valid account name.

Testing

# wbinfo -u

You should get a list of the users of the domain.

And a list of the groups. Be patient these queries can take time.

# wbinfo -g

Setup Authentication

nsswitch

file: /etc/nsswitch.conf

passwd:         compat winbind
group:          compat winbind
shadow:         compat

Testing

Check Winbind nsswitch module with getent.

root@linuxwork:~# getent passwd

root:x:0:0:root:/root:/bin/bash
...
LAB+administrator:x:10000:10000:Administrator:/home/LAB/administrator:/bin/bash
LAB+gast:x:10001:10001:Gast:/home/LAB/gast:/bin/bash
...

root@linuxwork:~# getent group

root:x:0:
daemon:x:1:
bin:x:2:
...
LAB+organisations-admins:x:10005:administrator
LAB+domänen-admins:x:10006:manuel,administrator
LAB+domänen-benutzer:x:10000:
LAB+domänen-gäste:x:10001:
LAB+linux-admins:x:10004:manuel
...

PAM

With this config you can access the workstation with local accounts or with domain accounts. On the first login of a domain user a home directory will be created. This PAM configuration assumes that the system will be used primarily with domain accounts. If the opposite is true (i.e., the system will be used primarily with local accounts), the order of pam_winbind.so and pam_unix.so should be reversed. When used with local accounts, the configuration shown here will result in a failed authentication to the Windows/Samba DC for each login and sudo use. This can litter the DC's event log. Likewise, if local accounts are checked first, the /var/log/auth.log will be littered with failed logon attempts each time a domain account is accessed.

This PAM configuration does not acquire a Kerberos TGT at login. To acquire a ticket, use kinit after logging in, and consider using kdestroy in a logout script.

file: /etc/pam.d/common-account

account sufficient       pam_winbind.so
account required         pam_unix.so

file: /etc/pam.d/common-auth

auth sufficient pam_winbind.so
auth sufficient pam_unix.so nullok_secure use_first_pass
auth required   pam_deny.so

file: /etc/pam.d/common-session

session required pam_unix.so
session required pam_mkhomedir.so umask=0022 skel=/etc/skel

file: /etc/pam.d/sudo

auth sufficient pam_winbind.so
auth sufficient pam_unix.so use_first_pass
auth required   pam_deny.so

@include common-account

Final configuration

Each domain needs a directory in /home/.

root@linuxwork:~# mkdir /home/LAB

One last thing

If you want to be able to use an active directory account, to manage your ubuntu box, you need to add it to the sudoers file. For that, you will need to edit the file /etc/group an add your username to the admin group, and whatever other group you need(plugdev,audio,cdrom just to mention a few). it will be like:

.......
admin:x:117:olduser,ActiveDirectoryUser
.......

Where olduser, is your current linux user, and ActiveDirectoryUser, is the new administrator. Another way to make a Domain Group, a sudoer in your ubuntu, is to edit the file /etc/sudoers (using the command 'visudo') and add the following line

%adgroup	ALL=(ALL) ALL

Where adgroup, it's a group from your active directory. take in mind, that spaces in the group name are not allowed, maybe you can use '%Domain\ admins' but i haven't tested.

Usage

Logon with DOMAIN+USERNAME, unless you included "winbind use default domain" in your smb.conf, in which case you may log in using only USERNAME.

login: LAB+manuel
Password: *****
...
LAB+manuel@linuxwork:~$

Automatic Kerberos Ticket Refresh

To have pam_winbind automatically refresh the kerberos ticket

Add the winbind refresh tickets line to smb.conf :

file: /etc/samba/smb.conf

#       winbind separator = +
winbind refresh tickets = yes
idmap uid = 10000-20000

And modify /etc/pam.d/common-auth:

file: /etc/pam.d/common-auth

auth sufficient pam_winbind.so krb5_auth krb5_ccache_type=FILE
auth sufficient pam_unix.so nullok_secure use_first_pass
auth required   pam_deny.so

Troubleshooting

If the Winbind PAM module in /var/log/auth.log says, that the AD-user is not existing, restart winbind. Probably it's best to restart the whole workstation.

root@linuxwork:~# /etc/init.d/winbind start

If when logging into the machine one gets a "no logon servers" error winbind\samba may not be starting properly. Try restarting them manually, and then logging in.

-If a manual restart works, then to fix this issue one needs to change scripts S20samba and S20winbind to S25samba and S25winbind in the /etc/rc2.d, rc3.d, rc4.d, rc5.d folders. The understanding is that this causes samba and winbind to startup later in the boot order for each runlevel. So that they start after S24avahi-daemon. If you then find that you must wait a bit before you can log in, you need to set "winbind enum users" and "winbind enum groups" in /etc/samba/smb.conf to 'no'.

name service cache daemon

The name service cache daemon (nscd) can interfere with winbind, as winbind maintains its own cache. Remove it.

sudo apt-get remove nscd

Some names or groups are not resolved with getent, but others are The range of your idmap parameter is not wide enough to encompass all the users or groups

idmap uid = 16777216-33554431
idmap gid = 16777216-33554431

External Docs

Also see Using Samba on Debian Linux to authenticate against Active Directory on randompage.org. It largely mirrors this page but has a little more detail.

Automated Methods

The SADMS package allows for automated joining to Active Directory through a GUI interface. [1]