Hallo Svit,
und hier für RC5 RC3420:
CPIB683 RC5 RC3420 Start of NetBIOS over TCP/IP failed with return code 3420.

This error indicates there is another computer on the network already using the name configured for the IBM i NetServer. Networking protocols do not allow two devices with the same name on the network. It can be caused by a TCP/IP address conflict in the Domain Name Server (DNS) or WINS Server entries for the IBM i system name or the NetServer name.

This error can also occur on IBM i systems with multiple partitions if the NetServers on each partition are configured to use the same name. Or, it can occur at upgrade time. For example, of you did a SAV of the IFS and copied IFS data that included the NetServer configuration files, from one partition to another. Then later, you had both partitions (or both systems) active and tried to start NetServer on both at the same time without having renamed the NetServer on one of the systems.

Note: NetServer configuration files are located in the /qibm/userdata/OS400/NetServer directory.

Other causes include configuring the NetServer to use the same name as the IBM i or as a Windows Workgroup or Domain having the same name as the NetServer. Try PINGing the NetServer name to see what TCP/IP address is being returned. However, remember that the NetServer name must be unique on the network in order for NetServer to start. If NetServer is active on another IBM i or if the name is assumed by something else on the network, NetServer will fail to start with CPIB683 RC5 RC3420 even if the PING command does not find anything for the name.

Changing the NetServer name to one that is not being used on the network will allow it to start successfully. If it is necessary to determine which device is reporting the name conflict, contact your service representative at the Rochester Support Center for assistance.