Difference between revisions of "Secure Authentication between Zimbra and AD"

(Secure Authentication between Zimbra and AD (self-signed certificate))
(Secure Authentication between Zimbra and AD (self-signed certificate))
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7. Restart AD server
To make sure the SSL is working, we can use '''ldp.exe'''. Click Start> Run > type ldp.exe and open it. At top left, click on "Connection" > "Connect...".

Revision as of 13:55, 18 October 2016

Secure Authentication between Zimbra and AD (self-signed certificate)

   KB 23061        Last updated on 2016-10-18  

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How to configure authentication with Active Directory using SSL.


To have better overview of the authentication with AD and how to configure it, check the following article


1. Review the following article to familiarize yourself with the authentication with AD from Zimbra side in AdminUI. The only difference is that in the "Active Directory Settings" , the Use SSL: tick box is selected:

3 ad ssl.JPG

2. After configuring the Domain Authentication with AD in Zimbra, we need to import the Zimbra CA to the DC:

  • Use tools such as WinScp to copy the /opt/zimbra/ssl/zimbra/ca/ca.pem file to the DC.
  • Copy the ca.pem file and rename it to ca.crt.

To install the certificate authority (CA) on the domain controller: , open the "Microsoft Management Console":

  • Start->Run > Type mmc. This will open the Microsoft Management Console.
  • Click "File" > "Add/Remove Snap-In..." to open the "Add Standalone Snap-in" dialog.
  • From the Available snap-ins on the left, select "Certificates" and press "Add".
  • Select "Computer account" and press "Next".
  • Select "Local computer" and press "Finish"
  • Click "Ok" to close the "Add/Remove Snap-in" dialog.

Once the "Certificates snap-in" is open, expand the "Certificates" node under "Trusted Root Certification Authorities". Right-click on the "Certificates" node, select "All Tasks" -> "Import...", and import the Certificate Authority ("ca.crt") you copied from Zimbra.

4 ad ssl.jpg

3. The next step is to create a csr. For this purpose we will use Microsoft's certreq utility. To generate csr, we need to create a *.inf file. Below is a sample *.inf file you ca use. Make sure that the "Subject" line contains the FQDN of the AD server.

  • Open a text editor and paste the following text, including the beginning and ending tags, into the file. Make sure no CR/LF character is added to the "Subject =" line when you copy and paste the text. Remove if any:

;----------------- request.inf -----------------

Signature="$Windows NT$" 


Subject = "CN=mail.example.com, OU=Organizational_Unit, O=Organization, L=City, S=State, C=Country" 
; Replace mail.example.com with the FQDN of your AD server's FQDN.
; Replace the remaining Subject attributes.
KeySpec = 1 
KeyLength = 2048 
HashAlgorithm = SHA256
Exportable = TRUE 
MachineKeySet = TRUE 
SMIME = False 
PrivateKeyArchive = FALSE 
UserProtected = FALSE 
UseExistingKeySet = FALSE 
ProviderName = "Microsoft RSA SChannel Cryptographic Provider" 
ProviderType = 12
RequestType = PKCS10 
KeyUsage = 0xa0 


OID= ; this is for Server Authentication 


  • Update the Subject attributes with appropriate values. For example: CN=mail.example.com

4. Once you have a inf file, generate a Certificate Signing Request (CSR) using certreq.

certreq -new ad.inf ad.csr  

5. Sign the certificate.

openssl x509 -req -days 365 -in ad.csr -CA ca.crt -CAkey /opt/zimbra/ssl/zimbra/ca/ca.key  -set_serial 01 -out ad.crt

6. Install the certificate.

From n Step 2, open the "Certificates snap-in", expand the "Certificates" node under "Personal". Right-click on the "Certificates" node, select "All Tasks" -> "Import...", and import the "ad.crt".

5 ad ssl.jpg

7. Restart AD server


To make sure the SSL is working, we can use ldp.exe. Click Start> Run > type ldp.exe and open it. At top left, click on "Connection" > "Connect...".

Verified Against: Zimbra Collaboration 8.6, 8.5, 8.0 Date Created: 31/05/2016
Article ID: https://wiki.zimbra.com/index.php?title=Secure_Authentication_between_Zimbra_and_AD Date Modified: 2016-10-18

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Wiki/KB reviewed by SME1 SME2 COPY EDITOR Last edit by Teodor Vizirov
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