How can I convert a PFX certificate file for use with Apache on a linux server?

With OpenSSL you can convert pfx to Apache compatible format with next commands:

openssl pkcs12 -in domain.pfx -clcerts -nokeys -out domain.ceropenssl pkcs12 -in domain.pfx -nocerts -nodes  -out domain.key   

First command extracts public key to domain.cer.
Second command extracts private key to domain.key.

Update your Apache configuration file with:

<VirtualHost 192.168.0.1:443> ... SSLEngine on SSLCertificateFile /path/to/domain.cer SSLCertificateKeyFile /path/to/domain.key ...</VirtualHost>

Additionally to

openssl pkcs12 -in domain.pfx -clcerts -nokeys -out domain.ceropenssl pkcs12 -in domain.pfx -nocerts -nodes  -out domain.key

I also generated Certificate Authority (CA) certificate:

openssl pkcs12 -in domain.pfx -out domain-ca.crt -nodes -nokeys -cacerts

And included it in Apache config file:

<VirtualHost 192.168.0.1:443> ... SSLEngine on SSLCertificateFile /path/to/domain.cer SSLCertificateKeyFile /path/to/domain.key SSLCACertificateFile /path/to/domain-ca.crt ...</VirtualHost>

To get it to work with Apache, we needed one extra step.

openssl pkcs12 -in domain.pfx -clcerts -nokeys -out domain.ceropenssl pkcs12 -in domain.pfx -nocerts -nodes  -out domain_encrypted.keyopenssl rsa -in domain_encrypted.key -out domain.key

The final command decrypts the key for use with Apache. The domain.key file should look like this:

-----BEGIN RSA PRIVATE KEY-----MjQxODIwNTFaMIG0MRQwEgYDVQQKEwtFbnRydXN0Lm5ldDFAMD4GA1UECxQ3d3d3LmVudHJ1c3QubmV0L0NQU18yMDQ4IGluY29ycC4gYnkgcmVmLiAobGltaXRzIGxpYWIuKTElMCMGA1UECxMcKGMpIDE5OTkgRW50cnVzdC5uZXQgTGltaXRlZDEzMDEGA1UEAxMqRW50cnVzdC5uZXQgQ2VydGlmaWNhdGlvbiBBdXRob3JpdHkgKDIwNDgpMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEArU1LqRKGsuqjIAcVFmQq-----END RSA PRIVATE KEY-----