Useful Tips for Troubleshooting AD

Some of the useful tips for troubleshooting AD

AD Replication

1. Repadmin /replsum – To verify the status of AD Replication

PS C:\> repadmin /replsum
Replication Summary Start Time: 2020-02-19 14:25:24

Beginning data collection for replication summary, this may take awhile:
  ......

Source DSA          largest delta    fails/total %%   error
 AD01               32m:59s    0 /  10    0
 AD02               37m:58s    0 /  10    0
 AD03               17m:20s    0 /   5    0

Destination DSA     largest delta    fails/total %%   error
 AD01               37m:58s    0 /   5    0
 AD02               32m:59s    0 /  10    0
 AD03               05m:41s    0 /  10    0

2. Push Changes to all AD Domain Controllers

Run the following command on the Domain Controller where the changes had made

repadmin /syncall AD02 /APeD

• /A Synchronizes all naming contexts that are held on the home server.
• /P Pushes changes outward from the specified domain controller.
• /e Synchronizes domain controllers across all sites in the enterprise. By default, this command does not synchronize domain controllers in other sites.
• /d Identifies servers by distinguished name in messages.

Verify which DC Users and Computer Authenticated to

1. Check which DC that user authenticated to

#Check which DC that user is authenticated 
$env:LOGONSERVER -replace "\\",""

2. Check which DC that computer is authenticated

#check which DC that computer is authenticated
nltest /dsgetdc:

 DC: \\AD02.aventislab.com
      Address: \\192.168.10.226
     Dom Guid: eaf8f27c-8453-423a-acf9-db2c0e40cd88
     Dom Name: aventislab.com
  Forest Name: aventislab.com
 Dc Site Name: HQ
Our Site Name: HQ
        Flags: GC DS LDAP KDC TIMESERV WRITABLE DNS_DC DNS_DOMAIN DNS_FOREST CLOSE_SITE FULL_SECRET WS DS_8 DS_9 DS_10
The command completed successfully

Verify Listening Ports

1. Verify Listening Ports for TCP Connections

Get-NetTCPConnection | Where-Object {($_.State -eq "Listen") -and ($_.LocalAddress -eq "0.0.0.0")} | Select LocalAddress, LocalPort

2. Verify Listening Ports for UDP Connections

Get-NetUDPEndpoint | 
    Where-Object { $_.LocalAddress -eq "0.0.0.0" }