Does OpenVPN require a certificate?

How to connect to OpenVPN with certificate?

I am trying to connect to my OpenVPN server using a certificate.

I installed OpenVPN on my home computer. I then opened the config file: sudo nano /etc/openvpn/server.conf And added this line to it: cert-authority /etc/openvpn/ca.crt I then tried to connect to the VPN by entering: openvpn --config server.conf And I get this error: /etc/openvpn/server.conf:2: command openvpn failed: exit status 1 How do I connect to OpenVPN using a certificate? The problem is with the OpenVPN config file, not your certificate. I just tried the same thing and it worked fine. If you want to see the OpenVPN config file use the following command:
Sudo openvpn --verbose --config server.

Does OpenVPN require a certificate?

(I had thought that if you're running one on Linux/OSX, it would just automatically find your certificate.)
Is this the right way to use OpenVPN with Linux? I'm not very familiar with networking (only used it for my internet connection), so please correct me if I'm missing something. If this isn't the right way to do it, can someone explain how I can authenticate against my VPN tunnel? I had expected it would be a lot easier than all of this, since I already have the certificates on file (and I'm not sure how they would work for this use). Thanks in advance! Yes, you need the certificates. With the certificate method, you could use a CA-signed certificate (with no user-managed private key at all). It's an alternative to the PK-certs method where you also don't store any user private keys, but uses CA-signed certificates only (without any user interaction).

Is this the right way to use OpenVPN with Linux? The Linux client (also called tunneling client) needs to be started on the computer you want to tunnel traffic to/from. The client connects to the OpenVPN server on another machine (you'll need to specify the server IP with the option -server address) and sends all traffic (not only the traffic you want to tunnel) to the server which forwards it to the destination (using tun or tap devices).

Since you want to tunnel a certain service, there must be some way to detect that service on your client. When you setup the connection, you choose one or more certificates, you make them available on the client and provide them to the server when requesting the tunnel.

When running your OpenVPN client on a server, the client won't use those certificates, since the server doesn't have a copy of them. The only certificates provided by the client to the server are the certificate and the CA-certificate that signed the client certificate. However, since you only created client certificates, you need the CA-certificates to create client certificates and make them usable by the server. This means, for your case, that you need the CA-certificates installed on your OpenVPN client.

How to select a certificate in OpenVPN?

I want to set up my openVPN configuration in a way so that it is really secure, but I have no idea how to do this.

As I understood, there are two components that I have to take into consideration when creating the certificates: 1) Which certificate authority should I trust? 2) Which certificate I should use for the server and the client? There's not a clear rule of thumb about which CA to use and how many CA certificates to generate, and what is the right number of certificates to use. I could generate lots of CAs but this may slow down start up significantly - which will affect its usability.

When using a self-signed server certificate this step can be skipped. The users connecting to you will receive the certificate they need. However, for a well configured and tested system it is preferred that the server certificate comes from a CA which can be verified by users connecting to the server.

What is the correct number of certificates that I should use when configuring OpenVPN? How can I figure out which CA to use? What criteria I should use to decide this? There is no right answer. It depends on many things. I've found that it usually works best to start with three certificates and see how that works. If it still doesn't work well, move on to 4 and so on.

The only way to know if you are set up properly would be to try it. If you decide you need more certificates after trying it out, it's possible that all your certificates will have an expiration date and might need to be regenerated. If you are not certain you would need a different number of certificates, try it out and see how it works. Also, if you don't need that many certificates, chances are it'll run just fine with fewer.

The most difficult question to answer. In my experiences it's somewhere between 3 and 7. If you're looking at running OpenVPN on a desktop system it's probably not worth the hassle to get that many certs.