This entry automatically starts the SAProuter during the system start and it ensures that the SAProuter is always started. Since the SAProuter should continue to run after R/3 is shut down no respective entry is included in the Stopsap Script. If you boot the R/3 several times, the system displays error messages when the SAProuter is started. You can ignore these error messages. The entry of the SAProuter in the Startup Script is a recommendation.
However, you can also start the SAProuter manually using saprouter -rThe corresponding routing table must be maintained in /usr/sap/saprouter/saprouttab. If you do not want an authorization check use the line 'P * * *'.
来源:http://www.sapsecurityonline.com/oss/saprouter_install.htm