Synology Reverse Proxy revisited (again..)

Work is taking too much time, so I haven’t updated the blog for a long time. Anyway a series of quick posts are on the publishing queue, and this is one of the first ones.

In February, my single disk installed in my Synology DS212 failed, after working for 7 long years. It still does work, but the bad sector error count is too high, and so can’t be used on the NAS anymore.

Anyway, this means that I needed to replace it, and this time I replaced it with two disks for RAID 1, instead of using a single disk on the NAS.

So why the long introduction?

Well installing new disks implied I needed to do a full DSM install from scratch which meant that several things changed from the previous DSM version that I had and be upgraded along, as the years passed by.

One of such things that changed, for the better, was the reverse proxy support using nginx and dropping the Apache http server use as the reverse proxy.

While reverse proxy now is supported out of the box on the Application portal, it only works for sub domain sites. For example If I want to reverse proxy Audio Station, it is quite easy to do it on the Control Panel -> Application Portal. The same is true for reverse proxy any other service running on the network. An example of such configuration is in this post: DSM 6.0 Reverse Proxy

What is not still able to do on the DSM interface is to map URL paths to other servers as I’ve explained on this post: Reverse proxy for URL paths. For example mapping the path /api to a back end server from the main Synology site.

Still, it is quite simple to do, and here are the instructions.

1. First we need to have ssh or telnet access to the DSM. Of course recommendation is to use ssh.
2. We need to change to this directory: /usr/local/etc/nginx/conf.d

   root@DiskStation:/usr/local/etc/nginx/conf.d# pwd
   /usr/local/etc/nginx/conf.d
   

3. Now we create in this directory a file that must have the following naming convention: www.our_name.conf.
   For example, let’s create the following file, named

   www.rproxy.api.conf

   with the following content:

   location ~ /api/ {
     proxy_pass http://192.168.4.20:3001;
   }
   

   This means that on the main Web Station site, the /api is passed out to the above server, in this case the http://192.168.4.20:3001.

4. We save the file and test now the configuration:

   root@DiskStation:/usr/local/etc/nginx/conf.d# nginx -T > /tmp/nginx.conf
   nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
   nginx: configuration file /etc/nginx/nginx.conf test is successful
   

   We can check the file /tmp/nginx.conf to see if there are no errors, and if the above configuration is in the file.

5. So all we need now is to restart the nginx server:

   nginx -s reload
   

And that’s it, our Web Station URL path /api should be redirected to the back end server.