Workaround for bogus dns server in tests

This should fix a false positiv response from bogus dns servers that
return a search site if a Domain does not exist.
We use an IP-address for testing in this case. The IP is 192.0.2.1 that
belongs to block 192.0.2.0/24 assigned as "TEST-NET", that should not
appear on the public internet. See RFC 3330 (Page 3).