Configure CentOS to authenticate to AD

Install the necessary packages

# yum install authconfig krb5-workstation pam_krb5 samba-common oddjob-mkhomedir sudo ntp samba-winbind-modules samba-winbind

Run authconfig to setup the initial authentication configuration

authconfig --disablecache --enablewinbind --enablewinbindauth --smbsecurity=ads --smbworkgroup=ITSOL --smbrealm=ITSOL.BIZ --enablewinbindusedefaultdomain --winbindtemplatehomedir=/home/teleena.local/%U --winbindtemplateshell=/bin/bash --enablekrb5 --krb5realm=ITSOL.BIZ --enablekrb5kdcdns --enablekrb5realmdns --enablelocauthorize --enablemkhomedir --enablepamaccess --updateall

Check your /etc/krb5.conf and test Kerberos authentication


default = FILE:/var/log/krb5libs.log 
kdc = FILE:/var/log/krb5kdc.log 
admin_server = FILE:/var/log/kadmind.log

default_realm = ITSOL.BIZ 
dns_lookup_realm = true 
dns_lookup_kdc = true 
ticket_lifetime = 24h 
renew_lifetime = 7d 
forwardable = true

admin_server =
kdc_server =

  kdc =
  admin_server =

[domain_realm] = ITSOL.BIZ = ITSOL.BIZ

To test Kerberos authentication:

# kinit bisser.todorov
# klist -a

The output should look like this:

Ticket cache: KEYRING:persistent:0:0
Default principal: bisser.todorov@ITSOL.BIZ

Valid starting Expires Service principal
04/07/2017 15:33:30 04/08/2017 01:33:30 krbtgt/ITSOL.BIZ@ITSOL.BIZ
 renew until 04/14/2017 15:33:26
 Addresses: (none)

Configure NTP

Kerberos authentication is very sensible about the time, so be sure your server’s time is synchronised. Configure and start NTP client. Comment all existing servers in /etc/ntp.conf and add your DCs

server iburst
server iburst
server iburst

Join the machine to the AD and test

# net ads join ITSOL.BIZ -U bisser.todorov
# net ads testjoin

The response should be “Join is OK”
Check your /etc/samba/smb.conf file

Setup a home folder

# mkdir /home/ 
# chmod 777 /home/

Grant linuxusers group sudo rights

# sudoedit /etc/sudoers

and add to the bottom:

%linuxusers ALL=(ALL) NOPASSWD:ALL

Configure SSHD for SSO

Check and if needed update your /etc/ssh/sshd_config

GSSAPIAuthentication yes
GSSAPICleanupCredentials yes
GSSAPIEnablek5users yes

Restart SSHD

Restrict access to only specific AD group members

Edit your /etc/security/access.conf

- : ALL : ALL

Test your setup



Another way of configuring authentication is using

# authconfig-tui

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