SAP Note 10456 - Error establishing connection to R/3 servers (SM51)

Symptom

Processes from other servers cannot be displayed in transaction SM51,
an error occurs when establishing the CPIC connection.
The error occurs primarily in connection with CPIC connections
to R/3 servers in the same system (e.g. when collecting the
statistics data).

Cause and prerequisites

The servers are not logged on to the msg-server with there host
name (that is, the name returned by the "hostname" command), but
instead with a different name. This can occur when the computers
have different network cards (lan0, lan1, X.25). Each of these
cards has a different name, and the message server sees the name of
the card used to log on.

To check whether this situation applies to you, examine the basic
list from SM51:
- The server name appears in the first column. This is formed from
__
- The second column contains the name under which the server is
logged on to the message server.
- The above situation applies when the hostname from the second
column is not identical with that contained in the server name.

The CPIC connection fails in this case, because the gateway
expects the servers to log on under the same name they are logged on
to the message server. In reality, however, they log on under the
name determined by the "hostname" command. As a result, the gateway
cannot assign the server correctly, and a timeout occurs during the
attempt to establish the connection.

Solution
As of Release 2.1K, the gateway attempts to take into consideration all of the hostnames. For this, the system uses the command netstat in UNIX enviroment and checks for NT in the Registry. If this is unsuccessful, you can use the parameter gw/alternative_hostnames as of Release 3.1F:

gw/alternative_hostnames=hosta,hostb,hostc

Key word: CPIC