Janus Telnet Server - Revision history

JDamon: added "screen" to "arbitrary-geometry" = arbitrary-screen geometry"

2020-04-23T17:04:29Z

added "screen" to "arbitrary-geometry" = arbitrary-screen geometry"

← Older revision		Revision as of 17:04, 23 April 2020
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	Since IODEV 21 is currently unused, add		Since IODEV 21 is currently unused, add
	<code>TNDEV=21</code> to the User 0 parameters to enable Telnet support.		<code>TNDEV=21</code> to the User 0 parameters to enable Telnet support.
	<li>If you want support for arbitrary-geometry Telnet clients, specify		<li>If you want support for arbitrary-screen geometry Telnet clients, specify
	<code>SIRTERM=1</code> in the User 0 parameters, if <var>[[SIRTERM parameter\|SIRTERM]]</var> is not already set there.		<code>SIRTERM=1</code> in the User 0 parameters, if <var>[[SIRTERM parameter\|SIRTERM]]</var> is not already set there.
	</ul>		</ul>

Alex at 23:44, 12 January 2020

2020-01-12T23:44:31Z

← Older revision		Revision as of 23:44, 12 January 2020
Line 1:		Line 1:
	Janus Telnet support allows you to set up one or more Telnet servers within		Janus Telnet support allows you to set up one or more Telnet servers within
	a <var class="product">Model 204</var> Online.		a <var class="product">Model 204</var> Online.
	<var>[[JANUS command\|JANUS]]</var> commands are used to define and start a TCP/IP		<var>[[JANUS command\|JANUS]]</var> commands are used to define and start a TCP/IP port
	for each <var class="product">Janus Telnet Server</var>.		for each <var class="product">Janus Telnet Server</var>.
	The <var class="product">Janus Telnet Server</var> supports only the tn3270 subset		The <var class="product">Janus Telnet Server</var> supports only the tn3270 subset

JAL at 19:40, 29 May 2013

2013-05-29T19:40:18Z

← Older revision		Revision as of 19:40, 29 May 2013
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	<li>The <var class="product">Janus Telnet Server</var> currently provides no		<li>The <var class="product">Janus Telnet Server</var> currently provides no
	facility comparable to the VTAM transfer facility available for VTAM terminals.		facility comparable to the VTAM transfer facility available for VTAM terminals.

	<li>If display of data in <var class="product">SirScan</var> is limited by IODEV type (that is, <code>IODEV15</code>),		<li>If display of data in <var class="product">SirScan</var> is limited by IODEV type (that is, <code>IODEV15</code>),
	the display will also pick up <var class="product">Janus Telnet Server</var> connections, which might not be desirable.		the display will also pick up <var class="product">Janus Telnet Server</var> connections, which might not be desirable.

JAL at 19:35, 29 May 2013

2013-05-29T19:35:10Z

JAL: /* See also */

2013-04-26T15:14:16Z

JAL: /* Configuring a Janus Telnet Server */

2013-04-25T19:12:12Z

Configuring a Janus Telnet Server

@@ Line 115: / Line 115: @@
 </ul>
 </ol>
 [[Category:Janus Sockets]]

JAL2 at 22:38, 21 February 2012

2012-02-21T22:38:31Z

← Older revision		Revision as of 22:38, 21 February 2012
Line 115:		Line 115:
	</ul>		</ul>
	</ol>		</ol>

			[[Category:Janus Sockets]]

JAL2 at 22:37, 21 February 2012

2012-02-21T22:37:08Z

← Older revision		Revision as of 22:37, 21 February 2012
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	When tracing 3270 datastreams using <var>[[JANUS TRACE]]</var>, one should be aware that		When tracing 3270 datastreams using <var>[[JANUS TRACE]]</var>, one should be aware that
	the 3270 datastreams are wrapped in Telnet/tn3270 datastreams, so they will contain extra "stuff."		the 3270 datastreams are wrapped in Telnet/tn3270 datastreams, so they will contain extra "stuff."
	The Telnet layer is described by ~~RFC 854 (~~[http://www.faqs.org/rfcs/rfc854.html RFC 854]),		The Telnet layer is described by [http://www.faqs.org/rfcs/rfc854.html RFC 854],
	and tn3270 is described by ~~RFC 1576 (~~[http://www.faqs.org/rfcs/rfc1576.html RFC 1576]).		and tn3270 is described by [http://www.faqs.org/rfcs/rfc1576.html RFC 1576].
	</ul>		</ul>

JAL2: Created page with "Janus Telnet support allows you to set up one or more Telnet servers within a `Model 204` Online. `JANUS` commands are used to..."

2012-02-21T22:19:28Z

Created page with "Janus Telnet support allows you to set up one or more Telnet servers within a <var class="product">Model 204</var> Online. <var>JANUS</var> commands are used to..."

New page

Janus Telnet support allows you to set up one or more Telnet servers within
a <var class="product">Model 204</var> Online.
<var>[[JANUS command|JANUS]]</var> commands are used to define and start a TCP/IP
for each <var class="product">Janus Telnet Server</var>.
The <var class="product">Janus Telnet Server</var> supports only the tn3270 subset
of the Telnet protocol.
That is, it will only serve clients that provide 3270 emulation via Telnet.
Janus Telnet servers can be accessed with Telnet, or more specifically a
tn3270 client of your choice, to gain 3270 access to <var class="product">Model 204</var>.
A tn3270 client will typically be running on an end-user's workstation.

Nowadays, almost all access to mainframe applications is via tn3270.
Typically, clients connect to a tn3270 server provided by the TCP/IP
stack for the operating system.
While most of these stacks are now provided by IBM, there are still
a few third-party stacks available, most of which provide their own
Telnet servers.
For Model 204 access, most tn3270 clients first connect to a service
such as VTAM or CMS, which then provides access to <var class="product">Model 204</var>.

Using the <var class="product">Janus Telnet Server</var> has some advantages over
using the Telnet server provided by the TCP/IP stack:
<ul>
<li>It eliminates the extra layer between TCP/IP and <var class="product">Model 204</var> —
either VTAM or CMS.
This reduces complexity and, possibly, CPU overhead.
For end-users, the extra step of connecting to <var class="product">Model 204</var>
after connecting to VTAM or logging on to CMS is eliminated — the user is connected
directly to <var class="product">Model 204</var>.
<li>It makes it much easier to determine the IP address of a 3270 user.
When tn3270 access is via VTAM, <var class="product">Model 204</var> only sees the
VTAM LU of the terminal.
Mapping this to an IP address can be difficult.
Maintaining a fixed IP address to LU name mapping in TCP/IP makes this more
feasible, but it is a maintenance headache.
<li>It reduces the number of thread types required in an Online.
Since <var class="product">Telnet Server</var> threads run in daemon threads, no special 3270
threads are required for 3270 access.
In fact, since CMS and TSO both provide tn3270 clients, no special thread
type is required for full screen access from CMS or TSO, either.
<li>The configuration of a <var class="product">Janus Telnet Server</var> is simpler and more dynamic
than the Telnet server provided by the TCP/IP stack.
<var class="product">Janus Telnet Server</var> ports can be started and stopped at will with the
<var>[[JANUS START]]</var> and <var>[[JANUS FORCE]]</var> commands.
In addition, the simple <var>[[JANUS DEFINE]]</var> command structure makes it easy
to set things like <var>[[BINDADDR (JANUS DEFINE parameter)|BINDADDR]]</var> or <var>[[TCPKEEPALIVE (JANUS DEFINE parameter)|TCPKEEPALIVE]]</var> that are difficult, if not
impossible, to set via the TCP/IP stack Telnet server.
<li>For <var class="product">Janus Network Security</var> customers, the <var class="product">Janus Telnet Server</var> can be trivially configured to use SSL.
<li>The Janus tracing facilities may be used to trace 3270 datastreams.
While obviously a somewhat esoteric capability, it can be quite useful on occasion.
When tracing 3270 datastreams using <var>[[JANUS TRACE]]</var>, one should be aware that
the 3270 datastreams are wrapped in Telnet/tn3270 datastreams, so they will contain extra "stuff."
The Telnet layer is described by RFC 854 ([http://www.faqs.org/rfcs/rfc854.html RFC 854]),
and tn3270 is described by RFC 1576 ([http://www.faqs.org/rfcs/rfc1576.html RFC 1576]).
</ul>

These are disadvantages of using a <var class="product">Janus Telnet Server</var>:
<ul>
<li>The <var class="product">Janus Telnet Server</var> currently provides no
facility comparable to the VTAM transfer facility available for VTAM terminals.
<li>If display of data in <var class="product">SirScan</var> is limited by IODEV type (that is, <code>IODEV15</code>),
the display will also pick up <var class="product">Janus Telnet Server</var> connections, which might not be desirable.
Of course, this is easily corrected by specifying <code>JAN:</code> followed by the
port name, instead of using <code>IODEV15</code> to limit <var class="product">SirScan</var> display.
For example, <code>JAN:WEB</code> would limit display to connections on port <code>WEB</code>.
</ul>

==Configuring a Janus Telnet Server==
<var class="product">Janus Telnet Server</var> is available as of <var class="product">Sirius Mods</var> version 6.9.
These are the configuaration steps:
<ol>
<li>Set User 0 parameters:
<ul>
<li>Even though <var class="product">Janus Telnet Server</var> runs full screen requests on daemon threads
(<var>IODEV</var> number set by the <var>[[SDAEMDEV parameter|SDAEMDEV]]</var> system parameter),
<var class="product">Model 204</var> typically considers an IODEV's type to be either line-mode or full-screen.
So the daemon threads that run Telnet requests will dynamically switch to
a different IODEV number while there is a connection.
Like <var>SDAEMDEV</var>, you must indicate in the User 0 CCAIN parameters
the IODEV number to be used for Telnet requests.

The <var>[[TNDEV parameter|TNDEV]]</var> parameter indicates the Telnet IODEV number.
Since IODEV 21 is currently unused, add
<code>TNDEV=21</code> to the User 0 parameters to enable Telnet support.
<li>If you want support for arbitrary-geometry Telnet clients, specify
<code>SIRTERM=1</code> in the User 0 parameters, if <var>[[SIRTERM parameter|SIRTERM]]</var> is not already set there.
</ul>
<li>Using a <var>JANUS DEFINE</var> command, define a Janus port that will provide Telnet service:

The following is a typical command for a Telnet server port:
<p class="code">JANUS DEFINE TNSERV 777 TNSERV 10 WSFQUERY
</p>
<ul>
<li>Specifying the <var>[[WSFQUERY (JANUS DEFINE parameter)|WSFQUERY]]</var> parameter is recommended to
provide support for non-standard terminal screen geometries.
A <var>JANUS START</var> for the port will then start the port and make direct Telnet
access to <var class="product">Model 204</var> available.
<li>As with any other port type, if a port number below 1024 is to be used, the
port might need to be reserved for the Online in the TCP/IP configuration.
The standard port number for Telnet is 23.
This port number will almost certainly be in-use on any mainframe on which
<var class="product">Model 204</var> will be running.

On a multi-homed mainframe, however, it might be possible to use port 23
on a specific host IP address for Janus.
The <var>BINDADDR</var> parameter is required to provide service on a specific IP address:
<p class="code">JANUS DEFINE TNSERV 23 TNSERV 10 WSFQUERY BINDADDR 198.242.244.13
</p>
<li><var>TCPKEEPALIVE</var> is an additional <var>JANUS DEFINE</var> parameter
worth setting in your <var>TNSERV</var> port definition, since this port is likely to be
held open for relatively long periods of time.
<li><var>[[AUTOSYS (JANUS DEFINE parameter)|AUTOSYS]]</var> is a <var>JANUS DEFINE</var> parameter
you can use in your <var>TNSERV</var> port definition
to specify a subsystem to be invoked after a login on the <var class="product">Telnet Server</var>.
</ul>
</ol>

← Older revision		Revision as of 15:14, 26 April 2013
Line 118:		Line 118:
	==See also==		==See also==
	<ul>		<ul>
			<li>[[Janus Sockets User Language coding considerations]]
	<li>[[Sample Janus Sockets programs]]		<li>[[Sample Janus Sockets programs]]
	<li>Socket-level interfaces:		<li>Socket-level interfaces:

← Older revision		Revision as of 19:35, 29 May 2013
Line 28:		Line 28:
	after connecting to VTAM or logging on to CMS is eliminated — the user is connected		after connecting to VTAM or logging on to CMS is eliminated — the user is connected
	directly to <var class="product">Model 204</var>.		directly to <var class="product">Model 204</var>.

	<li>It makes it much easier to determine the IP address of a 3270 user.		<li>It makes it much easier to determine the IP address of a 3270 user.
	When tn3270 access is via VTAM, <var class="product">Model 204</var> only sees the		When tn3270 access is via VTAM, <var class="product">Model 204</var> only sees the
Line 34:		Line 35:
	Maintaining a fixed IP address to LU name mapping in TCP/IP makes this more		Maintaining a fixed IP address to LU name mapping in TCP/IP makes this more
	feasible, but it is a maintenance headache.		feasible, but it is a maintenance headache.

	<li>It reduces the number of thread types required in an Online.		<li>It reduces the number of thread types required in an Online.
	Since <var class="product">Telnet Server</var> threads run in daemon threads, no special 3270		Since <var class="product">Telnet Server</var> threads run in daemon threads, no special 3270
Line 39:		Line 41:
	In fact, since CMS and TSO both provide tn3270 clients, no special thread		In fact, since CMS and TSO both provide tn3270 clients, no special thread
	type is required for full screen access from CMS or TSO, either.		type is required for full screen access from CMS or TSO, either.

	<li>The configuration of a <var class="product">Janus Telnet Server</var> is simpler and more dynamic		<li>The configuration of a <var class="product">Janus Telnet Server</var> is simpler and more dynamic
	than the Telnet server provided by the TCP/IP stack.		than the Telnet server provided by the TCP/IP stack.
Line 46:		Line 49:
	to set things like <var>[[BINDADDR (JANUS DEFINE parameter)\|BINDADDR]]</var> or <var>[[TCPKEEPALIVE (JANUS DEFINE parameter)\|TCPKEEPALIVE]]</var> that are difficult, if not		to set things like <var>[[BINDADDR (JANUS DEFINE parameter)\|BINDADDR]]</var> or <var>[[TCPKEEPALIVE (JANUS DEFINE parameter)\|TCPKEEPALIVE]]</var> that are difficult, if not
	impossible, to set via the TCP/IP stack Telnet server.		impossible, to set via the TCP/IP stack Telnet server.
	<li>For <var class="product">Janus Network Security</var> customers, the <var class="product">Janus Telnet Server</var> can be trivially configured to use SSL.
			<li>For <var class="product">[http://www.sirius-software.com/maint/download/jansslr.pdf Janus Network Security]</var> customers, the <var class="product">Janus Telnet Server</var> can be trivially configured to use SSL.

	<li>The Janus tracing facilities may be used to trace 3270 datastreams.		<li>The Janus tracing facilities may be used to trace 3270 datastreams.
	While obviously a somewhat esoteric capability, it can be quite useful on occasion.		While obviously a somewhat esoteric capability, it can be quite useful on occasion.
Line 66:		Line 71:
	</ul>		</ul>

			<p class="note">'''Note:'''
			To use <var class="product">Janus Telnet Server</var>, you must have licensed <var class="product">[[Janus TCP/IP Base]]</var> and <var class="product">[[Janus Sockets]]</var>. </p>

	==Configuring a Janus Telnet Server==		==Configuring a Janus Telnet Server==
	~~<var class="product">Janus Telnet Server</var> is available as of <var class="product">Sirius Mods</var> version 6.9.~~
	These are the configuaration steps:		These are the configuaration steps:
	<ol>		<ol>