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Rohan
Asked: 2015-01-02 00:43:12 +0800 CST

If a sub domain is secure with a SSL certificate, will the sub-subdomain also be secure?

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I have a standard SSL certificate I just purchased from Godaddy. Now it won't let me use a wild card for issuing the certificate for my domain. It says that the * wild card is not included in my product. Which means that I can only secure one domain like subdomain.example.com.

Now my question is that if I get the certificate issued for subdomain.example.com, will it be valid for subdomain2.subdomain.example.com also?

ssl

3 Answers

  1. Best Answer

    A certificate will only be valid for the names it was issued for. But, a certificate can contain multiple names so in your case you could get a certificate which contains both subdomain.example.com and subdomain2.subdomain.com or maybe just have *.subdmain.example.com. The latter would then match your subdomain2. Please not that a wildcard only matches a single label and that only a leftmost wildcard is possible, that is *.*.example.com is not possible and *.example.com will match subdomain.example.com but not subdomain2.subdomain.example.com or example.com.

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  2. No. Only subdomain.example.com and possibly www.subdomain.example.com will be covered by a "standard" certificate - you would need to purchase a wildcard domain at a higher price to cover all subdomains.

    You should be able to verify this by looking at the cert with a command like 

    openssl x509 -in certfile.crt -text -noout | grep "DNS"
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  3. Wildcard SSL certificate can secure your all sub domains.

    If your requirement is securing first level sub domains (sub1.domain.com, sub2.domain.com and sub*.domain.com), then certificate issue on any.domain.com

    You need to secure second level sub domains(aaa.sub1.domain.com, bbb.sub1.domain.com and any.sub1.domain.com), in that case issue certificate on *.sub1.domain.com

    For further information read this discussion - Wildcard SSL certificate for second-level subdomain

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