Taken from here:
https://buger.dread.cz/openvpn-expired-certificates.html
On 18.08.2020
Thank you man, very useful.
OpenVPN – expired certificates
2018-11-13 00:00 | tags: linuxvpnopenvpn
Server certificates
CA certificate
In case that CA certificate (lets name it ca.crt) gets expired, clients can’t connect to the OpenVPN server anymore. You need to generate new CA certificate signed with the same key (usually named ca.key) as the old one to avoid the need to regenerate all client certificates also.
Use following command to do so:
openssl x509 -in ca.crt -days 36500 -out ca.crt.new -signkey ca.key
- 36500days = 100years = validity of the new ca.crt
- rename ca.crt to ca.crt.old
- rename ca.crt.new to ca.crt
- restart / reload OpenVPN
- distribute new ca.crt to all clients
- check server certificate – it usually expires also, because both are generated during OpenVPN installation and usually have the same validity
Server certificate
In case that server certificate gets expired, simply generate new one using easy-rsa scripts:
. vars ./buid-key-server server
- reload / restart OpenVPN after that
Client certificate(s)
When client certificate gets expired, you can generate new one using previous .csr file this way:
. vars ./sign-req <certificate-name>
- send the new .crt file to the client
- client’s .key file is not changed => same password, we don’t need to know it to generate new .crt
https://buger.dread.cz/openvpn-expired-certificates.html