# Test DNS Resolution

Run this test if the system is experiencing problems resolving DNS hostnames. Successful DNS resolution is required by SIP devices and trunks; unsuccessful resolution may seriously impair SIP support.

To run the self-diagnostic test:

1. On the MBG main page, click the Troubleshooting tab, and click Diagnostics.
2. Beside DNS resolution test, click Run. Test results are displayed.

Parent topic: Diagnostics