FAQ: What is port fowarding?

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FAQ: What is port fowarding?

Unread post by Franklin » Thu Oct 19, 2006 12:58 am

Please consult with your IT Administrator before making changes with your router or routers!

Port fowarding is how information from outside of your network (from henceforth called WAN for this article) can access the servers on your LAN. Since Synology Servers are designed to perform many hosting functions, such as Web, Photo, or even FTP Services, the router has to be programmed to redirect WAN information to the Synology Server, which is a part of your LAN.

Because of the many different brands of routers out there, I cannot make a guide to cover each and every single one, please refer to the manufacture's website on how to do what I am about to explain.

First, you need to know what port to foward to the Synology Server, that information is located here.

Then on your router, I strongly recommended to assign a Static IP address to the Synology Server. Have the router assign the Static IP address based on the MAC address of the Synology Server, this way should the Server be powered down, it will still have the same address when it is restarted.*

For this guide, let's say the Synology Server IP address is and the WAN** IP address is And that we are going to foward Port 80 (HTTP) and Port 21 (FTP)

What you have to do is program the router that any data coming in from WAN on port 80 and 21, that they are automatically fowarded to and it's respective ports. After this is done, when a user types in into their web browser, they will see your web page (assuming that you enabled the web service on the Synology Server) or if the user types in "", the user will see the anonymous FTP share.

Of course with this ability with ports, let say you have 2 Synology Servers sharing 1 WAN address, and these two servers are part of two different departments, and both deparments have their own website. Here is for port fowarding two different servers.

Have the default address of (default port 80) go to Synology Server 1 which for this example will be

And the second address would be goto Synology Server 2 which will be

Please note that port 81 of the WAN is fowarded to port 80 of the LAN Server. So if a person wanted to browse the second site, the user will be required to have ":81" in the address, otherwise they would get the first server instead.

Typically speaking you can use what ever WAN ports to LAN ports at your own discreation, however, be sure that the WAN ports you want to use do not interfere with any other network services that are running with your network.

Here is where I assigned Static IPs to network devices on my network, based on the MAC address of each device

And here is the port foward screen.

*Side note: Yes, you can assign the static IP via the network settings of the Synology Server, however due to my experience in managing networks, I found that having the router to be the one spot to manage IP network settings of the is more effecient and it is easier to debug problems if say two servers are using the same Static IP address. However you assign the static IP is up to you.

**Need to know your WAN IP, click here.


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