Install a Let’s Encrypt SSL certificate on a Synology NAS

A while ago I wrote an guide on how to install a SSL from Namecheap onto your Synology. Soon after Let’s Encrypt support was added to Synology, I started getting requests for a guide.

The benefits of Let’s Encrypt certificates are that they are automated, short lifetimes (90 days) and that they are completely FREE!

Below is a quick guide on how to install Let’s Encrypt SSL on a Synology NAS!

Prerequisites before starting

  • A domain name of your own, such as If you don’t already own one I recommend using NameSilo or Namecheap to register one.
  • DDNS service configured. I’ll be using the Synology DDNS service as it’s free and I already use it.
  • Create a CNAME DNS record with your registrar (NameSilo or Namecheap) to forward requests to your DDNS service.
  • Enable port forwarding of from your router for port 80 to your NAS.

How to install a Let’s Encrypt SSL on a Synology NAS

For this guide I’ll be using my Synology DS1815+ running DSM 6.1.5-15254 Update 1 with 16GB RAM.

  1. First log into your DSM and navigate to: Control panel > Security > Certificate and click on Add
    Add certificate to Synology NAS
  2. Then select “Replace an existing certificate” to replace your existing or self-signed certificate.
    Synology replace existing certificate
  3. Now select “Get a certificate from Let’s Encrypt” and check “Set as default certificate
    Synology Get a certificate from Let's Encrypt
  4. Finally, enter a Domain Name and email address and click on Apply.
    Synology Let's Encrypt domain name

  5. At this point your Synology NAS will receive the Let’s Encrypt SSL and restart it’s web services automatically and you’ll then be able to access your NAS via the domain name.

    Every 90 days your Synology will automatically renew the Let’s Encrypt SSL cert for you.

    Let's Encrypt SSL installed on Synology NAS

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