HP-UX HB v13.00 Ch-10 - Network Services

HP-UX Handbook – Rev 13.00 Page 10 (of 26)
Chapter 10 Network Services
October 29, 2013
Well-Known Network Services
A standard HP-UX installation is capable of using several network services. Many but not all of
these are, or may be, launched from the Internet super daemon, inetd. Those which are not are
configured (in HP-UX) to start from configuration scripts in /etc/rc.config.d directory.
The names of the network services defined by the Internet Assigned Numbers Authority (IANA)
are provided in /etc/services and may also be served by either NIS or LDAP through their entries
through /etc/nsswitch.conf directives.
A TCP-based network service will have a LISTEN port; the output of netstat shows the ports
offering a TCP service
# netstat -a | grep LISTEN
tcp 0 0 localhost.49162 *.* LISTEN
tcp 0 0 *.135 *.* LISTEN
tcp 0 0 *.2121 *.* LISTEN
tcp 0 0 *.ovbbccb *.* LISTEN
tcp 0 0 localhost.49183 *.* LISTEN
tcp 0 0 *.shell *.* LISTEN
tcp 0 0 *.telnet *.* LISTEN
tcp 0 0 *.login *.* LISTEN
tcp 0 0 *.daytime *.* LISTEN
tcp 0 0 *.exec *.* LISTEN
tcp 0 0 *.auth *.* LISTEN
tcp 0 0 *.22 *.* LISTEN
tcp 0 0 *.discard *.* LISTEN
tcp 0 0 *.echo *.* LISTEN
tcp 0 0 *.time *.* LISTEN
The file /etc/services, lists most of the well-known services but the HP-UX distribution does not
map ssh in this file so it’s port (22) is not listed by name, the same is true of DCE endpoint
(135). Otherwise, we can see that the higher port numbers listed are not well-known services
because they are listening above port 1023.
For the services started from inetd, the inetd process itself actually owns all of the LISTEN ports.
Inetd will launch the service from a library routine upon demand. For instance, /etc/inetd.conf
will have an entry such as the following:
telnet stream tcp6 nowait root /usr/lbin/telnetd telnetd -b /etc/issue
Upon receiving a telnet request, inetd will launch /usr/lbin/telnetd to handle the incoming
connection.