Oracle 10.1, 10.2 and 11.1 do not support a hostname longer than 8 characters on HP-UX operating system

Symptons:
Listener dynamic registration will not work.

$ lsnrctl status

LSNRCTL for HPUX: Version 10.2.0.4.0 - Production on 04-JAN-2011 17:54:41

Copyright (c) 1991, 2007, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=sgh50460wk)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for HPUX: Version 10.2.0.4.0 - Production
Start Date                04-JAN-2011 17:52:17
Uptime                    0 days 0 hr. 2 min. 24 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Listener Parameter File   /u01/app/oracle/product/10.2.0/db_1/network/admin/listener.ora
Listener Log File         /u01/app/oracle/product/10.2.0/db_1/network/log/listener.log
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=sgh50460wk)(PORT=1521)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(KEY=EXTPROC0)))
Services Summary...
Service "PLSExtProc" has 1 instance(s).
  Instance "PLSExtProc", status UNKNOWN, has 1 handler(s) for this service...
The command completed successfully

Check the listener log, it tries to register to truncated hostname:(which is returned by "uname -n", instead of "hostname" command)

TIMESTAMP * CONNECT DATA [* PROTOCOL INFO] * EVENT [* SID] * RETURN CODE
WARNING: Subscription for node down event still pending
04-JAN-2011 17:52:17 * (CONNECT_DATA=(CID=(PROGRAM=)(HOST=sgh50460)(USER=oracle))(COMMAND=status)(ARGUMENTS=64)(SERVICE=LISTENER)(VERSION=169870336)) * status * 0
WARNING: Subscription for node down event still pending
04-JAN-2011 17:54:41 * (CONNECT_DATA=(CID=(PROGRAM=)(HOST=sgh50460)(USER=oracle))(COMMAND=status)(ARGUMENTS=64)(SERVICE=LISTENER)(VERSION=169870336)) * status * 0

Workaround:
Change the hostname to 8 or less characters, or use static service registartion.

$ cat $ORACLE_HOME/network/admin/listener.ora
# listener.ora Network Configuration File: /u01/app/oracle/product/10.2.0/db_1/network/admin/listener.ora
# Generated by Oracle configuration tools.

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = /u01/app/oracle/product/10.2.0/db_1)
      (PROGRAM = extproc)
    )
    (SID_DESC =
      (GLOBAL_DBNAME = ITOSIT2)
      (ORACLE_HOME = /u01/app/oracle/product/10.2.0/db_1)
      (SID_NAME = ITOSIT2)
    )
  )

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = sgh50460wk)(PORT = 1521))
    )
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
    )
  )