Recently we worked on saprouter issue.
We installed saprouter successfully but router processed stopped in particular time with creating core dump periodically.
but sapserv4 not allowed from our saprouter host.
We checked that there is a job AUTO_session* which execute in the same time periodically in the same sap system.
Then we stopped the stopped the job and issue was resolved.
But for permanent solution we upgrade the pacth of saprouter.