HP Integrity NonStop H-Series - Manual (Page 22)

NOTE: The PORTCONF file can be shared by two or more LISTNER processes. If the LISTNER
processes are running on different TCP/IP processes, TCP/IP port binding succeeds when LISTNER
processes are started. If the LISTNER processes use the same TCP/IP process and share the
PORTCONF file, then TCP/IP port binding fails when more than one LISTNER process is started.
Consider two LISTNER processes, A and B, which share a PORTCONF file and use the same TCP/IP
process. If you attempt to start B after starting A, the TCP/IP port binding fails and returns an EMS
message for error EADDRINUSE (4114). The LISTNER processes retry to start after a failure. The
number of EMS messages increase with each retry attempt. To avoid creating many EMS messages,
you can set the LISTNER^MAXTRY PARAM to limit the number of retries.
For example, the following command sets the retry number to three:
PARAM LISTNER^MAXTRY 3
The SERVICES file contains information on the known services available on the Internet.
After the accuracy of the PORTCONF file content is verified against the SERVICES file, the LISTNER
process listens to the configured ports, waiting for incoming connection requests from the remote
client. LISTNER continues to wait for new connections on that port and other well-known ports.
The TCP/IP subsystem (NonStop TCP/IP, Parallel Library TCP/IP, NonStop TCP/IPv6, or Cluster
I/O Protocols (CIP)) notifies the LISTNER process that a request is pending. When the LISTNER
process receives the notification, it starts the target server.
The target server creates a socket using hostname and source-port information, then accepts the
pending connection request on the newly created socket. The TCP/IP subsystem passes a connection
request to the LISTNER process only if the port through which the request was received is configured
in the PORTCONF file.
Each time a connection is made, connection-oriented services are provided by creating a new
LISTNER process. The LISTNER process creates the server process to provide the requested service.
The request may be received on a well-known TCP or UDP port.
The LISTNER process then is passed an argument of the form sourceport.sourcehost, where sourceport
is a decimal number and sourcehost is a hexadecimal number.
Data can pass between the target NonStop server and the remote client through the newly created
socket until either the remote client or the server terminates the connection.
Do not start the LISTNER process from a static or continuously available hometerm. If this condition
is not possible specify a local hometerm and IN and OUT files.
NOTE: The LISTNER process must be started by a user who has the user name SUPER.SUPER
and the user ID 255,255 in order for a remote FINGER client user to access the information in the
DOTPLAN and DOTPROJ files. Otherwise, the FINGER server cannot locate the user's default
subvolume in which these files are located.
Parallel Library TCP/IP and NonStop TCP/IPv6 offer a choice of four listening methods. The LISTNER
process is used in only one of these methods: the Standard Listening Model. For more information
about the Standard Listening Model, see the TCP/IP (Parallel Library) Configuration and
Management Manual or the TCP/IPv6 Configuration and Management Manual. These manuals
also contain information about starting the TELNET and TFTP servers.
As of J06.09 and H06.20, you can bind LISTNER to an IP address by using the LISTNER^HOST^IP
PARAM. The IP address assigned must be a valid numerical network address, that is, it has to be
an IPv4 address in dotted-decimal format or an IPv6 address in hexadecimal format.
To bind LISTNER to an IP address, before starting the LISTNER process, set the TACL PARAM
LISTNER^HOST^IP for the IP address. For example:
22 Introduction to TCP/IP Applications and Utilities