Purpose of HTTPS/SSL Certificate for DDNS?

[RSengine]

Noob question here - I have my ASUS router set up to serve as a VPN server (OpenVPN). My current DDNS setting under WAN shows "HTTPS/SSL Certificate" as "None". Is this a really bad idea security-wise or does it not matter?

 

[Mr Tvardovsky]

A couple days ago I had an issue with my Let's Encrypt certificate and was asking myself the same question. At the very least, here is what I noticed:

• OpenVPN server configuration file would ignore my DDNS address and use the "regular" public IP. In my case it changes whenever I restart the ISP modem. I assume when it happens, I wouldn't be able to connect to my server any more. My understanding is that OpenVPN requires that the DDNS is authorized in order to use it.
• Without a certificate, Asus Instant Guard wouldn't connect at all.

In any case, I did my best to get the certificate

 

[bbunge]

Noob question here - I have my ASUS router set up to serve as a VPN server (OpenVPN). My current DDNS setting under WAN shows "HTTPS/SSL Certificate" as "None". Is this a really bad idea security-wise or does it not matter?

Does not matter. The Let's Encrypt cert is not used with OpenVPN or Instant Guard. It is good to have if you are accessing other features of your router from the web.
DDNS on the other hand is needed unless you have a static WAN address. Sometimes the Asus DDNS does not work but it does come back up. Other DDNS providers are more reliable but Asus works for me.