A. Using System Settings
- Choose the Apple menu, and then click System Preferences and click Network.
- Choose the network service you use from the list on the left hand side of the window. If you use an Ethernet cable to connect to the Internet, for example, choose Ethernet from the list.
- Click on the Advanced button.
- Select the Proxies tab.
- Manually enter your proxy information by selecting Web Proxy and Secure Web Proxy protocols from the list
B. Using Dropbox Preferences
Alternatively, you can set Proxy settings for Dropbox only by manually entering proxy settings in the Dropbox preferences panel:
- Click on the Dropbox icon in the menu bar.
- Click on the gear icon and select Preferences... from the menu.
- Click on the Network tab.
- Fill in your proxy settings under the section appropriately labeled Proxy Settings.
Finally, note that Dropbox uses standard internet ports (80 and 443) to transfer data. However, many firewalls and security software (such as antivirus programs) will proactively block unauthorized or unknown internet services. Add Dropbox to your proxy or firewall settings as an exception to connect to the Dropbox service.
Let me know how this goes!