求助：OpenVPN握手失败问题排查（Ubuntu 16.04.03+Odroid设备）

Hey there, let's work through this OpenVPN problem you're hitting with your Odroid running Ubuntu 16.04.03 and PIA's pre-provided certificates. Since you suspect certificate-related issues, here are targeted steps to diagnose and fix things:

1. Double-Check Certificate Paths and Permissions #

First, confirm your OpenVPN config file points to the correct locations for PIA's certificate files (typically ca.crt, client.crt, and client.key). PIA's zip usually stores these in a subfolder, so your config should have lines like:

ca /home/your-user/pia-files/ca.crt
cert /home/your-user/pia-files/client.crt
key /home/your-user/pia-files/client.key

Next, make sure the user running OpenVPN has proper read access to these files—missing permissions often cause silent failures. Run these commands to fix permissions if needed:

sudo chown $USER:$USER /path/to/pia-files/*.crt /path/to/pia-files/*.key
sudo chmod 600 /path/to/pia-files/*.key  # Restrict key access for security
sudo chmod 644 /path/to/pia-files/*.crt

2. Validate Certificate Integrity #

Corrupted certificates from a bad download or extraction are a common culprit. Use openssl to verify their validity:

• Check the CA certificate for errors:

  openssl x509 -in /path/to/pia-files/ca.crt -noout -text
  

  If this throws an error, re-download the PIA zip package and extract it again carefully.
• Confirm the client certificate is properly signed by the PIA CA:

  openssl verify -CAfile /path/to/pia-files/ca.crt /path/to/pia-files/client.crt
  

  You should see OK as the output if the certificate chain is valid.

3. Fix OpenVPN Version Compatibility #

Ubuntu 16.04 ships with OpenVPN 2.3.x, which is older than modern versions. PIA's configs might include directives that need small adjustments for this older release. Try adding these lines to your config to improve compatibility:

tls-client
remote-cert-tls server
auth SHA256
cipher AES-256-CBC

Also, avoid any directives introduced in newer OpenVPN versions (like tls-crypt) unless you confirm they're supported in 2.3.x.

4. Test with a Minimal PIA Config #

Extra lines in your original config could be causing conflicts. Try a stripped-down config (replace the remote server address with your preferred PIA location):

client
dev tun
proto udp
remote us-east.privateinternetaccess.com 1198
resolv-retry infinite
nobind
persist-key
persist-tun
ca /path/to/pia-files/ca.crt
cert /path/to/pia-files/client.crt
key /path/to/pia-files/client.key
remote-cert-tls server
auth SHA256
cipher AES-256-CBC
verb 3

Run OpenVPN with this minimal config to see if it connects:

sudo openvpn --config /path/to/minimal-pia.conf

If it works, gradually add back lines from your original config to pinpoint the problematic setting.

5. Sync System Time #

Outdated system clock can trigger certificate validation failures (certificates have expiry windows tied to accurate time). Ensure your Odroid's clock is synced:

sudo timedatectl set-ntp on
timedatectl status

Check the Not After field in your CA certificate output (from step 2) to confirm it hasn't expired either.

If none of these steps resolve the issue, please share the exact error messages from your OpenVPN log and your full config file (redact any sensitive info like usernames/passwords). That will help narrow down the problem further.

内容的提问来源于stack exchange，提问作者cosmarchy