How to route packets from Wi-Fi to Ethernet on OSX?

Question

I have a trouble, configuring a home network.

Here is how my devices are connected together:

Internet
    ↕
Wi-Fi Router ↔ MacBook
    ↕
iMac ←ethernet cable→ Synology NAS

I have no ability to plugin NAS right into the Wi-Fi router.

The problem is that MacBook does not see NAS, because they are in different networks — I configured Wi-Fi Router to serve 192.168.10.0/24 addresses, and configured iMac's ethernet connection to use 192.168.20/24 network.

Is there a way to setup route from MacBook to the NAS?

Answer 1

You can ignore the WiFi<-> Ethernet part and just think about it as "How can I route traffic on a iMac?".

For that you need add a routing table entry on the iMac. Assuming the iMac runs OS X you can just search on OS X and routing and you will find posts like this one.

If you feel that it lack background information then I suggest reading This post on SE: SF.

---

An other option (One which allows you to access the Synology NAS when the iMac is turned off) would be to just add a switch.

 Internet
    ↕
Wi-Fi Router 
    ↕
 SWITCH   
    |
    | → Synology NAS
    |
    | → MacBook
    |
    | → iMac

Answer 2

Alternatively, just add a static route on your macbook. If you understand the basics of a network this is straight forward and you won't need to change your network or add devices.

Principle of adding a static route from your macbook is to tell it how to reach the NAS applicance/box.

Check this article below for a better description and walkthrough

http://hints.macworld.com/article.php?story=20060329085850170http://hints.macworld.com/article.php?story=20060329085850170

http://blog.irrashai.com/blog/2009/03/how-to-add-static-route-in-mac-os-x/