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TCP/IP Management. GO TCPADM. TCP/IP Management. Using the TCP/IP management tools to keep TCP/IP on your AS/400 robust, reliable and effective. Each option of the menu GO TCPADM has an associated command. GO TCPADM. GO CFGTCP WRKTCPSTS=NETSTAT
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TCP/IP Management GO TCPADM
TCP/IP Management • Using the TCP/IP management tools to keep TCP/IP on your AS/400 robust, reliable and effective. • Each option of the menu GO TCPADM has an associated command.
GO TCPADM GO CFGTCP WRKTCPSTS=NETSTAT CFGTCPAPP VFYTCPCNN=PING STRTCP STRTCPFTP ENDTCP STRTCPTELN STRTCPSVR SNDTCPSPLF ENDTCPSVR WRKSBSJOB
The components of TCP/IP processing on the AS/400 include: • The TCP/IP jobs • The physical connection over the line • The logical connection to the network • Optional SNMP services
TCP/IP Jobs • One of the jobs that is running named QTCPIP is the controlling TCP/IP job. • Other jobs such as QTFTP*****, QTGTELNETS, QTSMTP*****, QTWSG*****, QTLPD*****, QTPO***** , QTHTT***** also executed in QSYSWRK depending on your configuration.
The jobs that accompany QTCPIP are started in two ways: • Automatically, when the STRTCP is issued • Manually, through the use of the STRTCPSVR • TCP/IP functions that can be autostarted are FTP, Telnet, SMTP, LPD, HTTP, WSG ,POP. • STRTCPSVR : options for the SERVER parameter are *SNMP , *TELNET, * FTP , *SMTP, *LPD, *HTTP, *WSG , *POP
GO TCPADM • WRKCFGSTS To check the status of resources • VRYCFG To specify the names of the configuration objects to be varied on or off. • PING To confirm network connections and configuration • NETSTAT = WRKTCPSTS To display network status ( *IFC *RTE *CNN ) • DSPMSG MSGQ(QTCP) • DSPLOG LOG(QHST) • WRKSBSJOB(QSYSWRK)
PING • Can help find problems in logical connections • If the connection is successful ,receives a return reply. • If the packet never returns, there is no route from the source to the destination system and back again. This does not mean that TCP/IP is not configured correctly; it may mean that the routing is not established properly. • If the packet does make a successful round trip, the time that it takes to make the round trip may be excessive. You may need to examine your network for potential performance or bottleneck problem
VFYTCPCNN • After configuring a system for TCP/IP communications ,use PING command to ping the address ( or name) of the newly configured system. • A successful PING doesn’t necessarily indicate that the system is properly configured to communicate in the network (routing and DNS issues may remain), but it does indicate the TCP/IP protocol is loaded properly.
NETSTAT/WRKTCPSTS • The network status you can view are • TCP/IP interface status *IFC • TCP/IP route information *RTE • TCP/IP connection status *CNN
TCP/IP interface status • This display shows the interfaces currently configured on the system, including the loopback interface. • The interface status are: Active, Inactive, Ending, Failed ,Starting ,RCYPND, RCYCNL • It’s a good idea to print the interface status fro documentation purpose.
TCP/IP Route Information • The route destination • The subnet mask of the destination network ,sunnetwork, or system • The next hop IP address • A route available indication *yes --- the router is active and available *no --- the router is not available ,possibly due to an inactive interface or a nonfunctioning router.
TCP/IP Route Information • The Route Information detail display is valuable for determining whether a route exists in the AS/400 routing table. • For instance, PING is unsuccessful , you can examine the routing table to determine whether a route exists to the remote system .If the route is available, the problem might be in the TCP/IP configuration of the remote system, the routing on the remote system, or invalid routing information . If the route is not available, direct your attention to the routers and lines in the network that are logically between the source and the destination systems.
TCP/IP connection status • Listen--- the AS/400 is listening at the local port for an incoming connection • Established--- the connection is established and the system are communicating • Closed --- the connection has ended • Other states may be seen during a transition period • The ports( both remote and local) can use well-known names rather than a port number. These names are defined in the service table modified by the command WRKSRVTBLE
TCP/IP connection details • The number of bytes in and out ( from AS/400 perspective) for this connection. • The retransmission information gives the number of segments retransmitted by the AS/400 due to an acknowledgement not being received. • If the number of retransmission is higher than the number that has been historically present for this connection, it could be an indication that there are network problems.
TCP/IP connection details • The send window information identifies the current and largest size of the send window, or the number of bytes that can be transmitted without an acknowledgment. • A large send window indicates that the network is successfully transmitting large packets without the need for retransmission. • A small send window size means that the system has detected problems and has reduced the window size in an attempt to reduce the number of retransmissions.
Trouble Shooting • If the TCP/IP services you want to enable are not functioning Solution: Check QSYSWRK---- make sure the appropriate job is running in this subsystem
Trouble Shooting • If a server process has been running but no longer functions and cannot be seen when WRKSBSJOB QSYSWRK • Solution: Check the joblog for the missing process. By default joblogs go to the output queue QEZJOBLOG
Trouble Shooting • If you got physical connection problem • Solution: WRKCFGSTS ---- make sure *LIN, *CTL , *DEV are all in ACTIVE status. That enables communications across a line and start the QTCPIP job and associating the job with the line.
Trouble Shooting • If you got logical connection problem • Solution: PING VFYTCPCNN If the connection is successful ,you can receive a return reply NETSTATWRKTCPSTS
Trouble Shooting • If the connection is active and data is being transferred, F5 to refresh the screen should show a change in the byte counts. Otherwise probably means a recently broken connection, a network problem or a problem at the remote system.
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