macOS DNS Troubleshooting

Change your DNS settings to resolve router-level blocking of the BCS.

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Why do I need to change my DNS? Your router is currently blocking the BCS from working properly. This is a security feature that some routers have turned on by default. By changing your DNS settings to use Google's servers instead of your router's, you're asking a different "phone book" to look up the address the BCS needs — one that will allow our testing tool to work correctly.
1

Open Network Settings

Click the Apple menu (🍎) in the top-left corner.

Select System Settings (or System Preferences on older macOS versions).

Click on Network.

2

Select Your Active Network Connection

Choose the network connection you're currently using:

Wi-Fi if using wireless

Ethernet if using a cable

The active connection will show as "Connected" with a green dot.

3

Access DNS Settings

Click the Details button next to your active connection.

Click on the DNS tab.

4

Add Google DNS Servers

Click the + button under "DNS Servers" and add the following addresses one at a time:

Address Type
8.8.8.8 IPv4 (primary)
8.8.4.4 IPv4 (secondary)
2001:4860:4860::8888 IPv6 (primary)
2001:4860:4860::8844 IPv6 (secondary)

Remove any existing DNS servers by selecting them and clicking the − button, then click OK.

5

Apply the Changes

Click Apply to save your changes, then close the Network settings window.

6

Clear Your DNS Cache

Press

Command + Space
to open Spotlight search.

Type Terminal and press Enter.

Run the following commands:

sudo dscacheutil -flushcache
sudo killall -HUP mDNSResponder

Press Enter after each and enter your password when prompted.

7

Test the Change

In the same Terminal window, run:

nslookup bcs.visualware.com

You should now see Google's DNS servers (such as 8.8.8.8) listed instead of your router's address.

✓

You're Done!

Close all windows and try the testing tool again. Your computer will now use Google's DNS servers instead of your router's, which should allow the BCS to work properly.

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Still having problems? Contact us and provide screenshots of the steps taken above. On macOS, press Command + Shift + 4 to capture a selected area.