Error in RFC destination after IP address has changed

After the IP address of a host was changed, the RFC destinations using the host as a target do not work.

Cause and conditions

If you enter the host name when you create an RFC destination (for example hs0330), it is stored in table RFCDES (destination administration) as an IP address.
This speeds up the connection of a remote function call, since the host name does not repeatedly have to be converted into an IP address. Furthermore, the length of a host name can be any length, which is not suitable for storage in table RFCDES.

However, problems do occur if the IP address of the target host changes. When this happens, you must adjust the corresponding RFC destinations.

Notes:

• If you do not want the name of the target host to be stored as an IP address in the database table RFCDES, you must enter it as an SAP router name (/H/hs0311 instead of hs0311). In this case, the host name is stored as the SAP router name in table RFCDES.

• If you do not use the SAP router notation when you maintain the destination, the system performs the following conversions internally:

• The host name is converted into its IP address. If the conversion is successful, the IP address is stored as the target host address in table RFCDES.

• The IP address is converted into its domain name server name (DNS name). It is possible that the DNS name is not the same as the host name.
  For example, Windows NT displays host names in uppercase or in long notation. Thus hw1426 would be displayed as HW1426 or hw1426.wdf.sap-ag.de. The DNS name is only used for display in the RFC destination.
  The way in which the IP address is represented as a DNS or host name has no effect on RFC communication.

Solution

If the target host name is not entered as an SAP router name and you change the IP address of the host, you must adjust the relevant RFC destinations.