Some Yealink phones will ring if they detect certain Port Scans. you can disable this by disabling 'Allow IP Call'
The information below relates to most Yealink phones but may vary depending on the model and firmware version
Steps to 'Disable IP Call'
Login to the Yealink phone
We've done these steps on a Yealink T26
Click on 'Features'
If you can't see 'Features' then you may have to update the firmware
Then click on 'General Information'
Scroll down to 'Allow IP Call' and set to 'Disabled'
Click the 'Confirm' button