HP-UX Internet Services Administrator's Guide (May 2010)

The tcpd Daemon

The tcpd daemon monitors access to a service, logs the host name and the remote user

name owning the connection, and performs some additional access control checks.

After tcpd checks the connection, the wrapper invokes the desired server program

and exits.

Enabling tcpd

You can use either of the following methods to enable tcpd:

1. Edit each entry in the /etc/inetd.conf file to include the tcpd server program,

/usr/lbin/tcpd. The server program field in the /etc/inetd.conf file

indicates the absolute path name of the server that inetd executes. For example,

consider the following entry for the telnet service in the /etc/inetd.conf

file:

telnet stream tcp nowait root /usr/lbin/telnetd telnetd

Edit this entry to include the tcpd server, /usr/lbin/tcpd instead of the telnet

server, /usr/lbin/telnetd, as follows:

telnet stream tcp nowait root /usr/lbin/tcpd /usr/lbin/telnetd telnetd

NOTE: If you specify this entry without the absolute path of telnetd

(/usr/lbin/telnetd), tcpd searches the telnetd binary in the

/usr/lbin/wrapper directory.

The last component of the path name, /usr/lbin/telnetd telnetd, is used

for access control and logging. When the telnet service is requested, inetd

invokes the tcpd server instead of invoking the telnet server. tcpd performs

access control checks and verifies whether the connection is valid. Then, it invokes

the telnetd server. Similarly, you can change the entries for other services to

include the tcpd server.

After making the relevant changes, you must reconfigure inetd using the following

command on the command line:

# inetd -c

2. Move the service daemon to the /usr/lbin/wrapper directory, and move tcpd

to the location of the service daemon. You need not make any changes to the

/etc/inetd.conf file. For example, you can enable the ftpd service with tcpd

by executing the following commands at the command prompt:

# mkdir /usr/lbin/wrapper

# mv /usr/lbin/ftpd /usr/lbin/wrapper

# cp tcpd /usr/lbin/ftpd

40 TCP Wrappers