MacOS Active Directory Authentication Issue

Alberto Torres
Alberto Torres used Ask the Experts™
We have several MacOS devices running Mojave that are having trouble staying connected to our AD Domain. These machines are bound and join AD successfully at first. We are able to login with domain credentials, however, after a while, these machines will stop authenticating domain credentials. We have 3 locations that are all macos devices and the other 2 locations do not have this issue, only this one location.

All 3 locations share the same ad domain but each site does have its own domain controller.

Any advice on troubleshooting steps to see why this one location keeps "losing" its authentication to AD?
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eridzoneIT Administrator

Are you also running DHCP on your DC, can you please confirm the scope of lease having dc's(for DNS) in correct orders.

I also have the similar issue in one of our IT Lab consists of only iMacs, some of them had this issue and was resolved by disabling Wifi and going through Ethernet. See if it helps
OS X tends to do that with AD.  You must rebind them periodically.

You should set your AD accounts as Mobile accounts to cache them, so they can continue to log in, after AD is lost. This only mitigates the effect so that you don't need to rebind them all the time, and so the user account profile does not disappear. from the Mac.  All AD accounts are Mobile accounts, because they are external to the Mac.
Open the Directory
Unlock it so you can make changes.
Select Active Directory
Click on the Pencil icon to edit.
Click on the show advance options.
Check the Create mobile account at login.

You may also want to force a domain controller in the Administrative tab.  You can also set the Administrative users, as you would on Windows.
Peter HutchisonSenior Network Systems Specialist

Check AD Sites and Services, make sure that all the appropriate subnets for your orgnaisation is configured to use for each site and Domain Controllers are assigned to the correct sites. This will ensure that clients will use the Domain Controller is nearest to them.
For macs, use Wired rather than wireless connections to ensure continuous connectivity. Turn off wireless in the Network system preferences, if not used.Also , make sure that the IP address of your DC servers are used rather than external DNS servers or DNS in routers.
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@eridzone  Yes we are using DHCP and the DNS servers on the scope options are set correctly. Our Student Lab ( all iMacs) are currently on ethernet. The issue still happens on ethernet for us.

@serialband For our staff who are assigned a macbook pro, we made sure to put them on mobile accounts as you said and works for them. Our bigger issue is really with the student lab where students may log in for the 1st time at several different times in the year.

I guess what makes this stranger is that we don't experience this issue at our other 2 all mac locations.
This suggests that you have different network setups or network issues at the location in question.
If WiFi and Ethernet is connected at the same time is can cause problems, but the usual cause I have experienced is losing timesysnc, which usually is the Mac losing timesync, and sometimes the DCs losing sync (usually in virtualised environments).

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