Computers unjoin domain after each reboot

Question

This is my config:

controller.mydomain.local (Domain Controller)
     IP Address   : 192.168.1.1/24

computer1.mydomain.local
     IP Address   : 192.168.1.2/24 
     DNS Server 1 : 192.168.1.1 
     DNS Server 2 : 8.8.8.8 

computer2.mydomain.local
     IP Address   : 192.168.1.3/24 
     DNS Server 1 : 192.168.1.1 
     DNS Server 2 : 8.8.8.8

All these computers have the same username and password. After each reboot I can't ping computer2.mydomain.local or computer1.mydomain.local or controller.mydomain.local from computer1 and computer2. I need to disable and enable network adapter 2 or 3 times, sometimes I need to reboot another time to be able to ping domain name or computer names.

Esa Jokinen · Accepted Answer · 2017-06-08T13:25:01.650

No, your computers are not unjoining the domain i.e. disappearing from your Active Directory. The problem here is related to your DNS configuration, alone. I believe that ipconfig /all shows:

Ethernet adapter Local Area Network:

   Connection-specific DNS Suffix  . : mydomain.local
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   IPv4 Address. . . . . . . . . . . : 192.168.1.2(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . : 192.168.1.???
   DHCP Server . . . . . . . . . . . : 192.168.1.1
   DNS Servers . . . . . . . . . . . : 192.168.1.1
                                       8.8.8.8
   NetBIOS over Tcpip. . . . . . . . : Enabled

The problem here is that your DHCP server gives Google Public DNS 8.8.8.8 as a second DNS server. Google Public DNS doesn't know anything about your local DNS names. Every time a client computer tries to lookup computer2.mydomain.local from there it is doomed to fail. And this happens every time when the response from the first DNS server takes longer than a second.

Every time you reboot / disable&enable the adapter / unplug&plug the cable, it flushes the DNS cache, which causes you to believe it solved the problem, while the client only got temporarily the better condition of these two, i.e. the only DNS server that has the mydomain.local zone.

Go to Administrative Tools > DHCP > controller.mydomain.local > Scope [192.168.1.0] > Scope Options and Remove 8.8.8.8 from 006 DNS Servers. (You should also add your another Domain Controller there instead, as you always should have at least two domain controllers.)

Then, if you wish to use 8.8.8.8 somewhere, add it as a forwarder in your DNS server.

Computers unjoin domain after each reboot

1 Answers1