Hello Andreas,
What kind of options did you start dbsrv17 with?
And what kind of OS is used on the virtual machine?
You can check on communication behavior of dbsrv17 by the -z option.
The -z option displays diagnostic communication messages, and other messages, for troubleshooting purposes.
"-z database server option"
http://dcx.sap.com/index.html#sqla170/en/html/3bcf1cd06c5f1014bcadbab61e41e0a2.html
And you can get further information with the LogFile connection parameter of the client-side.
"LogFile (LOG) connection parameter"
http://dcx.sap.com/index.html#sqla170/en/html/814507d56ce210149a4cdfe2297831ec.html
Regards,
Koichi