inetd_enable=YES in Software Add UPCA in Software inetd_enable=YES

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inetd_enable=YES use none none integrated tobuild none for none Barcode FAQs The default conf none for none iguration of inetd does not listen for any incoming connection. The configuration file contains sample configuration lines for popular services, but is commented out. Hence, you should uncomment any line, depending on the service you want to enable, and restart the inetd daemon.

For example, to enable FTP service on your host using inetd, you should uncomment the appropriate line (remove the # mark from the beginning of the line) in the /etc/inetd.conf file:. ftp stream tcp nowait root /usr/libexec/ftpd ftpd l You may have not none for none iced that there are two lines for most of the services listed in the inetd configuration file. Each line specified in the inetd configuration file should listen to TCP (IPv4) or TCP6 (IPv6), if it is supported by the service, so that you can specify each service over IPv4 or IPv6, separately. In the previous example, we enabled FTP service over TCP/IPv4.

In order to reload the inetd configuration (if running), the following command should be issued:. # /etc/rc.d/inetd reload You can verify t none for none he inetd services using the sockstat(1) utility as follows:. # sockstat -l grep inetd root none none inetd 797 5 tcp4 *:21 *:*. This shows that inetd is listening to TCP4 port 21 (which is FTP service).. [ 204 ]. 13 . In case you want none none to add a service to inetd that is not listed in the default configuration file, you can take any of the lines as a sample and modify it to suit your own daemon. The first parameter in each line (in this case, ftp) is the service name. The service name is then looked up from the /etc/services file, to find out the actual port number that should be listened to.

In this example, the second parameter, stream, specifies the socket type. A socket type can be one of stream, dgram, raw, rdm, or seqpacket. A typical service running on TCP uses stream, while UDP socket type is dgram.

The third parameter in this example is protocol tcp. For UDP services, this parameter should be changed to udp..

It is advisable to use tcp4, udp4, tcp6 ,udp6, tcp46, or udp46 instead of tcp or udp, to specify whether a service should work on IPv4 or IPv6 (or both) protocol stacks.. The fourth param none for none eter in each line (in this example, nowait) specifies whether inetd should wait for the server to exit before listening for new requests. Generally, services running on TCP protocol should use nowait and UDP should use the wait option. As TCP is a connection-oriented protocol, inetd accepts the new connection request and passes the connection to the daemon.

Once a new connection request is received, inetd launches a new instance of the daemon, and passes the connection to the daemon. Unlike TCP, the UDP is connection-less and therefore the wait option is used. The fifth parameter on the line (root in this example) is actually the user whom daemon will launch, with its privilege.

You may have noticed that almost all sample services in the inetd.conf file will run with root privilege, which is not a good practice in the production environment..

It is proposed t hat each daemon to run with a specific user having limited privilege (for example, only have permission on required files and directories), so that in case of any security breach, the scope of the damage will be limited to that specific service and related files and directories.. Finally the last none none parameter on the configuration line is the full path to the daemon program including the command line parameters (if applicable).. [ 205 ]. Network Services Internet Servers To have a quick look at a custom inetd service, the following example shows that inetd should listen to a port 69 UDP (tftp service), which is a dgram socket using root user privileges to run the tftpd binary at /usr/libexec/tftpd with appropriate parameters:.
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