[Samba] Question about certificates on Samba AD/DC

gabben gabbenx at gmail.com
Sun Jun 14 20:28:14 UTC 2020

Hi Igor,

You certainly don’t want a different CA for each DC, and you typically do want an individually generated certificate and private key for each server. 

PKI is typically a tree hierarchy, which is a critical feature in the trust relationships across any environment. You want one (root) CA, and possibly 1-3 intermediate CAs depending on the complexity of your infrastructure ( intermediate CA certificates are capable of signing host specific certs.). Each DC, (and each web server, application server you deploy with SSL/TLS protected services) needs to present its own server certificate (+ the full chain of certs used to sign its server cert) to clients so that clients can check validity of the server cert for themselves (based on the trusted certs in the client CA trust store).

Then the root and the intermediate certificate authority (CA) certs get pushed in the the root trust storage facility on every  host OS in your environment, so that they all trust a certificate presented by any server that they connect to which has a cert signed by your CA infrastructure.

The level of complexity you need to engage in depends on the size and needs of your environment. If you have simple needs in a smaller environment, take a look at OpenVPN project’s “easy-rsa”

Good luck. 

> On Jun 14, 2020, at 1:15 PM, Igor Sousa via samba <samba at lists.samba.org> wrote:
> Thanks Gabben and Andrew. I've understood but a new question emerged: Each
> DC server on my domain has a different pair cert/key and a different CA
> cert after deployment, correct?
> If so, is it a best practice to generate new cert for each DC server and
> sign them with a unique CA? OBS: Every DC servers belongs to the same
> domain.
> --
> Igor Sousa
> Em dom., 14 de jun. de 2020 às 16:46, Andrew Bartlett <abartlet at samba.org>
> escreveu:
>> On Sun, 2020-06-14 at 16:24 -0300, Igor Sousa via samba wrote:
>>> Hi everyone,
>>> I have a question about certificates generated on Samba AD/DC
>>> deployment.
>>> After all server configuration, I notice that there are ca.pem,
>>> cert.pem
>>> and key.pem on /usr/local/samba/private/tls directory. I realize the
>>> ca.pem
>>> and cert.pem have 2 years validity. Will Samba AD/DC generate
>>> automatically
>>> new certs before this time over? Or, must I have to generate them
>>> manually?
>> No, they will need be automatically renewed.
>> So yes, you need to generate them manually.
>> The original intention was that the certificates be replaced by the
>> administrator.
>> However, I think we would accept patches to extend the initial validity
>> on the autogenerated certificates, given that replacement almost never
>> happens.  This makes more sense then to renew them, as that would break
>> software which has the current certificate manually accepted, and
>> potentially break a manually installed certificate.
>> Andrew Bartlett
>> --
>> Andrew Bartlett                       https://samba.org/~abartlet/
>> Authentication Developer, Samba Team  https://samba.org
>> Samba Developer, Catalyst IT
>> https://catalyst.net.nz/services/samba
> -- 
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