vCenter server 7.0 cannot fetch SSL Certificates from domain controllers using openssl

Hello Community,

I am trying to join vCenter server 7.0.2 to AD over LDAP, however getting error "Can't contact LDAP server."

As a part of troubleshooting, it came out that vCenter cannot fetch the SSL certificates from the domain controllers and openssl gives following error:


root@myvcsa01 [ ~ ]# /usr/bin/openssl s_client -connect




no peer certificate available


No client certificate CA names sent


SSL handshake has read 0 bytes and written 215 bytes


New, (NONE), Cipher is (NONE)

Secure Renegotiation IS NOT supported

Compression: NONE

Expansion: NONE

No ALPN negotiated


    Protocol  : TLSv1.2

    Cipher    : 0000




    Key-Arg   : None

    PSK identity: None

    PSK identity hint: None

    SRP username: None

    Start Time: 1636711093

    Timeout   : 300 (sec)

    Verify return code: 0 (ok)



- All required ports are open between the vCenter and domain controllers and there's no traffic blocked.


So any idea on this? Where the problem is and how to fix it?


Thank you!
Vikramaditya J
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1 Reply
VMware Employee
VMware Employee

The port is typically 389 for LDAP connections and 636 for LDAPS connections.

Use the same command with port 389 and check. Engage you AD/DC/Firewall Team to see what's they see when you run the command.


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