* fix issue of 'Error writing to QHostAddress("")'

(cherry picked from commit 9450b97c94af8c4919151ae91e9c7601b74e95ad)

* remove obsolete comments

(cherry picked from commit 7ff3b0049b9f91f39f5e764c92058ba1c0484308)

* add comment on why the additional condition check is required.

(cherry picked from commit 149e19b7c90f178f8a7e8a544243ce7acd642fe8)