The JSM_OPEN Built-In Function is always executed first. It is used to connect the JSM client to the Java Service Manager and to start a thread for the service. Each client will have its own thread.
The server argument is optional for the connection. If the server argument is not supplied, or if the argument value contains blanks, then the remote host and port number is obtained from the data area JSMCLTDTA on IBM i or from file jsmcltdta.txt on Windows or Linux.
The server argument can have any of the following values:
The JSM_OPEN must be executed before the JSM_COMMAND can be used.
The JSM_OPEN Built-In Function performs a DNS lookup to resolve the host name address. Using a dotted decimal IP address does not get around this DNS lookup.
If the JSM_OPEN Built-In Function is slow to open a connection then you could have a DNS lookup issue. Add an entry to the local host table to improve performance.
TCP/IP connection performance can be improved if the registered DNS servers are available and performing well.
Change TCP/IP Domain
Host name search priority *LOCAL
Domain name server
Internet address 18.104.22.168
If the first Domain Name Server (DNS) in the list does not respond, the second DNS server in the list will be contacted. If the second DNS server does not respond, the third DNS server will be contacted.
See IBM i - Network Performance for further information.