When you are in a corporate LAN, access to the outside is often restricted. HTTPS is allowed, yet other applications like SSH or OpenVPN might not be. As well, you want to run several of these services onto your Synology box. Choosing which one will use TCP port 443 could be a hard judgement to make. Luckily, there is
SSLH to the rescue.
Note: with DSM7, it is no longer possible by default to open port 443 (which is below 1024) with the provided user (sh-sslh). You will get a "0.0.0.0:https:bind: Permission denied" error when changing port 30000 to 443. The fix is to change your portforwarding in your router to NAS_IP:30000 instead. The below tutorial was making the SSLH service listen to port 443 with the other services running on localhost:443.
As a consequence, changing the sslh.cfg file and the NGINX files is no longer needed, so everything below can be ignorred.
Caution! Playing around with your SSL port could possibly break the access to your DSM if nginx fails to restart. Therefore, I strongly recommend the following actions:
- Never put your SSH server to listen ONLY onto 127.0.0.1. Never.
- Never change all of your services (HTTPS, SSH, OpenVPN) at the same time, unless your 100% sure your config is correct.
- Open up temporarily the Telnet service, just in case
- Make sure you don't lock yourself out with your firewall rules onto your Synology
- Backup the original config files before starting making changes. cp -p config.file config.file.ori will do.
0. Make sure you have the
Synocommunity repository installed under your Package Center. Open up an SSH connection to your Synology and
make yourself root.
1. Download and install the SSLH package. By default, the configuration file is at
/usr/local/sslh/var/sslh.cfg and needs to be adapted. Make a backup copy of the file first.
2. Go to your terminal and edit the file with vi
vi /usr/local/sslh/var/sslh.cfg
3. Change the IP address (under host: "0.0.0.0") to your IPv4 address of the Synology. Do NOT yet change the port. Leave it onto 30000 as default.
4. Check if the services listed are using the correct port numbers and adapt if needed. Save the file.
5. Now go to the Package Center of DSM again and stop and start SSLH.
6. Go to your terminal and verify if SSLH is running properly by running the command:
netstat -an | grep 30000
Expected output:
root@server:/# netstat -an | grep 30000
tcp 0 0 192.168.0.5:30000 0.0.0.0:* LISTEN
7. Check if HTTPS is currently running and listening to the IPv4 address:
netstat -an | grep 443
Expected output:
root@server:/# netstat -an | grep 443
tcp 0 0 0.0.0.0:443 0.0.0.0:* LISTEN
tcp6 0 0 :::443 :::* LISTEN
This now means that nginx is still listening onto the IPv4 address for HTTPS. Let's change that.
8. Open your web browser and browse to your Synology IP for both HTTP as for HTTPS: http://yourip and https://yourip
Confirm that this is working properly.
9. Go to the nginx config directory (/usr/syno/share/nginx) and backup the following files: DSM.mustache, WWWService.mustache and server.mustache
10. Use vi to change nginx from listening to 0.0.0.0:443 to 127.0.0.1:443 only, by making it look like this:
listen 127.0.0.1:443
DSM.mustache
WWWService.mustache
server.mustache
Repeat this for all 3 files and save your changes.
11. Restart nginx from the command line:
synoservicecfg --restart nginx
You can monitor into /var/log/synoservice.log if things restarted properly. Typical output should be:
2017-01-10T19:04:33+01:00 server synoservicecfg: service_restart.c:21 synoservice: restart [nginx] ...
2017-01-10T19:04:34+01:00 server synoservicecfg: service_restart.c:52 synoservice: finish restart [nginx].
12. Verify that HTTPS is only listening onto localhost (127.0.0.1)
root@server:/usr/syno/share/nginx# netstat -an | grep 443
tcp 0 0 127.0.0.1:443 0.0.0.0:* LISTEN
tcp6 0 0 :::443 :::* LISTEN
13. Refresh the browser screen for your HTTPS. It should not show any website anymore.
14. As a final step, change your SSLH config file and set the port to listen from 30000 to 443. Restart SSLH in the Package Center by doing a stop and start. Or do it command line:
synoservicecfg --restart pkgctl-sslh
15. Verify that SSLH is now listening onto your IPv4 address with port 443.
root@server:/usr/syno/share/nginx# netstat -an | grep 443
tcp 0 0 192.168.0.5:443 0.0.0.0:* LISTEN
tcp 0 0 127.0.0.1:443 0.0.0.0:* LISTEN
tcp6 0 0 :::443 :::* LISTEN
16. You can test your HTTPS, OpenVPN and SSH. All should perfectly route through the SSLH multiplexer.
