Configuring a Routable Domain

Clients wishing to migrate to Office365 will usually utilise Azure Active Directory Connect to form part of the migration, this will synchronise Active Directory to Azure to be used throughout the Office365 suite.

Previously it was best practise to append domain names with .local or similar as routable domains were not previously required.

Synchronising users with non-routable suffix’s will fail generating alerts and the users will not be synchronised. Prior to migration its possible to highlight the risk using Microsoft’s IDFix tool found here.

In order to amend the current domain the following steps should be taken:

Add a new UPN suffix

Open Active Directory Domains and Trusts
Right click the root > Properties
Add routable domain suffix (E.g - l-w.tech)

Change UPN Suffix for users**

The following PowerShell command will edit all user account withing the specified OU with the new UPN suffix:

###
#Replace edgeitc.local and l-w.tech
###

$OUUsers = Get-ADUser -SearchBase "OU=FirstOU,OU=RootOU,DC=edgeitc,DC=local" -Filter {UserPrincipalName -like '*edgeitc.local'} -Properties userPrincipalName -ResultSetSize $null

$OUUsers | foreach {$UPNUpdate = $_.UserPrincipalName.Replace("edgeitc.local","l-w.tech"); $_ | Set-ADUser -UserPrincipalName $UPNUpdate}