I have two droplets at digitalocean. Both servers are LEMP, however one is completely blocked (http & https) with a firewall. I want to make HTTP requests between the two servers, however there is gonna be sensitive data transferred between the servers, and I don't want this getting sniffed by other droplets hosted at the same center. How can I go about securing the data transferred between the two servers? I tired thinking of a way to setup HTTPS, however you can't get a signing on a private IP. Any help is appreciated! Thanks!
Perhaps you can create a host record for a local domain. Call it server1.local and server2.local. Then you can goto http://www.selfsignedcertificate.com/ and create a self-signed certificate for each domain. Then add each others certificate to the trusted certificate store. Now the servers can communicate via the new domains. Since the certificates are trusted by each server you will have a secure connection between the two machines. There is no need to pay for a certificate since you have access to both machines that need to trust the certificates. This will not create a security hole either since the servers will authenticate each other by the certificate that was added to the trust store.