Multiple certs on one server (was: Re: Firefox says Peer's Certificate has been revoked)

David Newman dnewman at
Wed Dec 22 08:18:37 MSK 2010

On 12/20/2010 05:03 PM, David J. wrote:
> On the topic of SSL;
> Is there any possible way to run multiple certs on one IP?
> I dont think this is possible as per the SPEC; But I am not an expert.

Me neither, but there's nothing wrong with this. The CN in a cert is
bound to a string such as a hostname, not to an IP address. (The string
could also be someone's name, or any other text, including an IP address
-- but as a text string). SSL works above the network layer and doesn't
care about L3 addressing.

So, if you've got multiple virtual hosts on a single IP address, you
have a couple of choices:

a. Use one cert per virtual host

b. Use one cert for all virtual hosts and chain them using the
subjectAltName parameter in openssl.cnf. This is what I did on the
server in the original post in this thread.

Here's a thread from a few years ago when I was getting (b) set up:

You can buy chained certs that do this from multiple registrars; I got
one from GoDaddy but concur with others' description about the GD web site.


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