<body bgcolor=#ffffff>
<title>Internet Services</title>
<center><img src="images/inetd.gif"></center><br>
<h2><i>This help page is incomplete</i></h2>
<hr>
<h3>Introduction</h3>
This module allows you to manage and setup internet services such as
<tt>telnet</tt>, <tt>ftp</tt> and <tt>finger</tt>. Every internet service
has a name, port number and protocol (such as <tt>telnet</tt> on
<tt>tcp</tt> port 23). Many services also have a server program to handle
network connections to that services. <p>
Services with an associated program are controlled by the Unix
<tt>inetd</tt> daemon, which listens for network connections on behalf of
all its services. When a connection is received, the server program is
started to handle data from the new connection. <p>
Not all internet services are managed by this module. Servers that receive
many connections such as HTTPD, SMB or NFS are run separately to avoid
having to start a new process for each request. These services can be
configured using other Webmin modules, such as <a href=/samba/>Samba</a>
or <a href=/apache/>Apache</a>. <p>
The main page for this module lists all the internet and RPC services
on your system. Services with a program assigned are displayed in bold.
The list of internet services, RPC services and programs are taken from
the files <tt>/etc/services</tt>, <tt>/etc/rpc</tt> and
<tt>/etc/inetd.conf</tt>. <p>
<hr>
<h3>Creating a New Service</h3>
To create a new internet service, click on the <tt>Create New Service</tt>
link below the list of active services. This will take you to a form
in which the details of the new service can be entered :
<ul>
<li><b>Service Name</b><br>
Every service must have a unique name and protocol pair.
This means that two services can have the same name only
if they use different protocols. <p>
<li><b>Protocol</b><br>
The communications protocol used by this service. Almost all
internet services use the <tt>TCP</tt> protocol, and the rest
use <tt>UDP</tt>. <p>
<li><b>Port</b><br>
Every service has a port number which must be unique within
the protocol used by the service. The port number must be between
0 and 65535 for both <tt>TCP</tt> and <tt>UDP</tt>. <p>
<li><b>Aliases</b><br>
A list of alternative names used to refer to this service. An
alias cannot be already used as the name or alias of an existing
service with the same protocol. <p>
</ul><p>
Internet service names can be used instead of hostnames in commands
such as <tt>telnet</tt>. For example, you can type <tt>telnet foo.bar.com smtp</tt> to connect to port 25 on the host <tt>foo.bar.com</tt>, assuming
the <tt>smtp</tt> internet service is defined correctly. <p>
For services with an associated program, you must choose the <tt>Use the
program below</tt> option ???
<ul>
<li><b>Program</b><br>
Some rare services are handled internally by <tt>inetd</tt>.
However, for almost all new services that you create the full
path to the program to execute for the service should be given
here. <p>
<li><b>Arguments</b><br>
Command line arguments to pass to the program above. The first
argument should be the program name, and the rest other parameters
to pass. <p>
<li><b>Wait mode</b><br>
This determines if <tt>inetd</tt> will wait until the program
is complete before starting any others or not. For most services,
this should be <tt>Don't wait</tt>. <p>
<li><b>Execute as</b><br>
The username of the user the server program should be run as.
Most servers will need to be run as <tt>root</tt>. <p>
</ul><p>
When a new service is added, it will not take effect immediately. You must
click the <tt>Restart Inetd</tt> button on the main page for the addition
to be applied. <p>
<hr>
<h3>Editing an Existing Service</h3>
To edit a service, click on the service name from the list on the main page.
This will display the same form used for creating a service to allow you
to edit the service details. You can also click on the <tt>Delete</tt>
button at the bottom of the page to delete the service. <p>
Be careful when editing or deleting existing system services such as
<tt>telnet</tt> or <tt>ftp</tt>. Changing these may make it impossible
to login to your machine (or worse). <p>
When a service is modified, it will not take effect immediately. You must
click the <tt>Restart Inetd</tt> button on the main page for the changes
to be applied. <p>
<hr>
<h3>Creating and Editing RPC Programs</h3>
In general, you will never need to create or edit RPC programs on your
system. However, if you do the procedure is similar to creating and
editing internet services. <p>
The form for editing and creating RPC programs will always contain at
least the following fields :
<ul>
<li><b>Program Name</b><br>
A unique name for this RPC program (within the same protocol). <p>
<li><b>Number</b><br>
Every RPC program has a unique program number, determined when
the program is written. <p>
<li><b>Aliases</b><br>
Other names that can be used to refer to this RPC program. <p>
</ul><p>
Some operating systems (such as Solaris) allow a server program to be
associated with an RPC service. This program will be run by <tt>inetd</tt>
when it receives a request for the program. <p>
If your system supports RPC server programs started by inetd, the following
fields will also be visible :
<ul>
<li>???
</ul>
<hr>
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