Please let me summarize the problem more accurately (hopefully):
Windows: - One single machine Windows Vista - Windows user is "admin" (it is local administrator) - Machine has an IP-address of 192.168.178.20 (obtained from my WLAN router via DHCP)
SQL Server: - SQL Server 2008 is installed - SQLEXPRESS runs under my admin user - configured: "Windows Authentication" - IP-addresses: 192.168.178.20 is activated and active (port 1433)
What happened: - Logged on to the machine using admin - started sqlcmd using following command (test.sql contains some sql): sqlcmd -S 192.168.178.20 -E -i test.sql -> Error: "Login failed. The login is from an untrusted domain and cannot be used with Windows authentication."