# How to Renew Certificate for WebDAV Server on Synology NAS

**It expires every 90 days...**

Use **Tailscale VPN**, then SSH into your NAS to regenerate the certificate for WebDAV.

> Source:
> [Reddit Zotero Tutorial](https://www.reddit.com/r/zotero/comments/15b5kay/tutorial_for_synology_nas_storage/)
> [Tailscale Forum](https://forum.tailscale.com/t/stuck-on-provision-tls-certificate-for-internal-tailscal-services/4101)

---

### 1. **Clear Previous Certificate**

* Open: **Synology Control Panel > Security > Certificate**
* Delete the expired certificate
* **Enable Tailscale VPN**
* Use **PowerShell** (Windows) or **Terminal** (macOS) to SSH into NAS

---

### 2. **SSH into NAS**

ssh galencky@100.73.210.37 -p6969

> Enter your Synology NAS password.

---

### 3. **Create New Certificate and Private Key**

#### Old method

sudo tailscale cert galennas.tail3ad28.ts.net

#### 🖥 macOS Terminal:

ssh galencky@100.73.210.37 -p6969 '
sudo tailscale cert \
  --cert-file=/volume1/homes/galencky/galennas.tail3ad28.ts.net.crt \
  --key-file=/volume1/homes/galencky/galennas.tail3ad28.ts.net.key \
  galennas.tail3ad28.ts.net
'

#### 🪟 Windows PowerShell:

ssh galencky@100.73.210.37 -p 6969 `
"sudo tailscale cert `
--cert-file=/volume1/homes/galencky/galennas.tail3ad28.ts.net.crt `
--key-file=/volume1/homes/galencky/galennas.tail3ad28.ts.net.key `
galennas.tail3ad28.ts.net"

> This will generate:
>
> ```
> /volume1/homes/galencky/galennas.tail3ad28.ts.net.crt
> /volume1/homes/galencky/galennas.tail3ad28.ts.net.key
> ```

---

### 4. **Configure the Certificate on Synology**

* Go to: **Control Panel > Security > Certificate**
* Choose **Import Certificate**

* Certificate: `galennas.tail3ad28.ts.net.crt`
* Private Key: `galennas.tail3ad28.ts.net.key`
* Apply it to the **WebDAV Server**

---

### ✅ WebDAV Paths in Use

* **Zotero**
[https://galennas.tail3ad28.ts.net:9488/homes/galencky/Large Files or Datasets/Zotero](https://galennas.tail3ad28.ts.net:9488/homes/galencky/Large%20Files%20or%20Datasets/Zotero)

* **Notability**
[https://galennas.tail3ad28.ts.net:9488/homes/galencky/Large Files or Datasets/Notability](https://galennas.tail3ad28.ts.net:9488/homes/galencky/Large%20Files%20or%20Datasets/Notability)

---

Now it should work 😄 Let me know if you'd like to automate this with a scheduled renewal script.