SSL Certificate format

Ever since we first started putting SSL certificates on our system we have use Verisign. Process was simple. We got the certificate from Verisign, we put it in the IFS, we loaded it into DCM and applied it to servers/services. We are now for the first time using a Comodo certificate and the Comodo site is asking what format we want the certificate file in. In the past with Verisign that was never asked and I think we just told Verisign that we used an IBM i and we got the correct certificate. The only reference I can find to the format that DCM wants to use is an obscure reference to X.509. Can anyone confirm that X.509 is the format of the certificate we want to get from Comodo? It is listed as a format but there are also 6 other formats listed and our security expert (Windows and Cisco) also said that there are tools to convert certificates to additional formats. I see file formats for .pem, .crt, .ca-bundle, cer, p7b, p7s, pfx. Never realized there were so many. We have also received .cer files from Verisgn but that is not an option on the Comodo site.

Thanks
Mike Cunningham

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