Thanks, but the problem is solved!

Each SQL instance has its own FIXED port-nr.

Greetings

Marcel

I could resolve my problem. This is what I did:

open odbcad32, new System-DNS, typed in the servername (without instancename), in the next window I configured the port-nr in the clientconfiguration,...

thank you for your replies!

There are no default instances on this server, only 8 named ones!

All the services seem to be ok! lmhosts and hosts-file are standard, there are no...