SSL certificate renewal when moving servers

Posted on 2009-05-02
Last Modified: 2013-11-08
We have moved a secure website to another server (HTTPS) and presumably need to regenerate a new CSR record for the new box and have Comodo reissue the certificate.

Two questions:
1. If this the correct procedure or can we just reuse the old cert (same domain name)
2. Does anyone know if Comodo re-issue certificates for free?

Question by:brothertom
    LVL 30

    Expert Comment

    if its using a different ip address then its a new cert if its using the same ip address then posibly a re-issue

    Author Comment

    No, its a new IP, so will have to get a new one.

    As a matter of interest, what underlying information is used to create the private key?
    LVL 30

    Expert Comment

    the ip address imho
    LVL 33

    Accepted Solution

    as long as the domain name (NOT IP address) has not changed, it shouldn't need a new certificate.
    just export the old key+cert from the old box (a pkcs #12 file is standard there) and import to the new.

    the private key contains NO host information - it is purely an encryption tool.
    the public key is calcuated from the private key and again, is not host specific

    the public *certificate* however contains the domain name (or ip address, or whatever you asked the CA to sign, but usually domain name), the company name, the CA's certificate ID (and name), the duration of the certificate, and the public key. it is digitally signed by the private key of the CA to ensure validity.

    but to be certain, inspect the old certificate (just visit the site in almost any browser, and do "view certificate") and check the subject name is the site domain name. that is all the browser checks (and it is the browser that cares, not the server)

    Author Comment

    Yes, you right - the certificate is validating the site name not the IP.
    However, Comodo have very kindly agreed to issue anyway, so thats the way we'll go with this.


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