External connection to Domain Controller - Secure LDAP 636

I have a domain controller with secure LDAP available on port 636

However we have internal dns for our outside domain setup to be remoteDC.ourdomain.com
that hostname is set to direct to the internal IP and is opened through external firewall to allow connection into the internal Domain Controller.

Using LDP.exe internally I can connect to the remoteDC.ourdomain.com but externally cannot, even though firewall rules are there to allow.

Would this have to do with any certificates or the remotedc.ourdomain.com not matching the internal domain controller called DC01?
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AmitIT ArchitectCommented:
What tool are you using to check from outside? You basically need to use ldaps when using 636.

or use ldap explorer.
garryshapeAuthor Commented:
It's a third party tool that has a built in LDAPS connectivity built in
I just don't know if lack of having the certificate locally on the non domain computer would prevent any connection at all.
AmitIT ArchitectCommented:
If you are able to connect via ldp. That rules out cert issue. Focus on firewall. Make sure 636 is allowed.

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garryshapeAuthor Commented:
Yeah internally I can but users' externally cannot who are permitted via an IP block rule
garryshapeAuthor Commented:
Yeah was firewall related, networking dept. had to fix it.
Didn't think it'd be a complicated on the Windows side of things...
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