Well it is possible to transfer an SSL certificate from a Windows (IIS)
environment to a Linux (Apache) environment. Within a shared hosting
environment, (at least the majority of them) it will not be possible to
install the SSL certificate to the hosting account without the help of your
hosting provider. The SSL installation requires an IP be allocated to your
domain within the server's configuration, unless deployed with SNI, and a
VirtualHost entry routing requested to port 443 (TLS/SSL) for your domain
on that IP will have to be created. Needless to say these configurations
affect the server as a whole and are chargeable services so most providers
will not provide you direct access to do this. If your provider uses
Vdeck then this
is the case.
That being said it is well worth the money to have your hosting provider
complete this configuration for you and the related services are generally
pretty cheap. Most providers will average around $20.00 per year for all
the services required to have your SSL function on their servers.
I would request information from your provider regarding the
installation to see if it is the right solution for you.
As a note Windows (IIS) SSL certificates are commonly PKCS#12/PFX
Formated. The PKCS#12 or PFX format is a binary format for storing the
server certificate, any intermediate certificates, and the private key in
one encryptable file. PFX files usually have extensions such as .pfx and
.p12. PFX files are typically used on Windows machines to import and export
certificates and private keys. Linux (Apache) will use PEM formatted
certificates.The PEM format is the most common format that Certificate
Authorities issue certificates in. PEM certificates usually have extentions
such as .pem, .crt, .cer, and .key. They are Base64 encoded ASCII files and
contain "-----BEGIN CERTIFICATE-----" and "-----END CERTIFICATE-----"
statements. Server certificates, intermediate certificates, and private
keys can all be put into the PEM format.
Apache and other similar servers use PEM format certificates. Several
PEM certificates, and even the private key, can be included in one file,
one below the other, but most platforms, such as Apache, expect the
certificates and private key to be in separate files.
I would not bother with the conversion prior to contacting your hosting
provider as they can obtain the PKCS#12/PFX certificate from you and then
covert it when installing it on the server. You should only have to provide
the PKCS#12/PFX formatted certificate.