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Re: Hostname does not match common name problem
--On Saturday, March 14, 2009 12:21 PM +0100 Michael StrÃder
I have a problem with an LDAP server that I need to connect to. I
have the required certificate stored on the client but I am getting
the following error message:
"TLS: hostname (A.xyz123.com) does not match common name in
Personally I'm scared of accepting wildcard certs for security reasons.
As far as I understand it, RFC4514 section 3.1.3 allows wildcards
thus the connection should work, shouldn't it?
It's RFC 4513, section 3.1.3. And there it says:
The server's identity may also be verified by comparing the reference
identity to the Common Name (CN) [RFC4519] value in the leaf Relative
Distinguished Name (RDN) of the subjectName field of the server's
certificate. This comparison is performed using the rules for
comparison of DNS names in Section 18.104.22.168, below, with the exception
that no wildcard matching is allowed.
So wildcard DNS names in CN is explicitly not allowed. You can try with
wildcard patterns in the subjectAltName cert extension.
Except that most cert vendors put the wildcard in CN and not
subjectAltName. I note everything I ever tested with a wildcart cert
accepted this *except* OpenLDAP. So I submitted an ITS somewhere back in
OpenLDAP 2.2 land to allow this, and it has been in place ever since, and
works to this day AFAIK.
Principal Software Engineer
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