In case you have a crt certificate including your key and you need a p12
openssl pkcs12 -export -in hereyourcertificate.crt -inkey hereyourkey.key -out yournewp12certificate.p12
openssl pkcs12 -in ABC.pfx -nocerts -out privatekey.pem -nodes
openssl rsa -in privatekey.pem -out server.key
ssh -L AAAA:SERVER:BBBB GATEWAY AAAA=Lokaler Port SERVER=IP Remote Server BBBB=Remote Port GATEWAY=IP Gateway
Tunnel in Tunnel
ssh -p "SSH Port at Machine A" -l "your username at Machine A" -L 127.0.0.1:22222:127.0.0.1:444 "IPD/DNS of Machine A"