check port 53 usage on QVD network only

git-svn-id: https://svn.qindel.com/repos/main/projects/qindel/QVD/src/trunk@23623 4046b530-fbad-4e16-af16-ee11f0b55167
fix syntax error

git-svn-id: https://svn.qindel.com/repos/main/projects/qindel/QVD/src/trunk@23635 4046b530-fbad-4e16-af16-ee11f0b55167