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Reverse Telnet TNA Device

 
Hal Kuff
Occasional Advisor

Reverse Telnet TNA Device

Hi, sorry to do Back to the Future.. but I know how to create a service on a DS900 to expose a port.. how do I get to the port (10.10.10.10 port 2010) for say port 10 on the server from a program on the OpenVMS system? Where does the TNA mapping take place? Basicaly we have outbound LAT modems and need LAT to go away...
13 REPLIES 13
Jon Pinkley
Honored Contributor

Re: Reverse Telnet TNA Device

Hal,

Are you using the DS900 still? I would try connecting to tcp port 30xx the ip address associated with the terminal server, where xx is the port #. I.e. to connect to async port 5 on the DS900, connect to tcp port 3005. You have to have the port configured for remote access.

Why the need to have LAT go away? Are there routers between the terminal server and the OpenVMS system? Does there need to be (distance, etc.)?

Jon
it depends
John Gillings
Honored Contributor

Re: Reverse Telnet TNA Device

Hal,

Telnet doesn't work like LAT. Although you can create a TNA device in much the same way as you create a LAT application port, you can't just open it from an application. I've never quite understood the reasons for this, but that's all academic. Banging your head against that brick wall won't help.

One (ugly) way around this uses the pseudo terminal interface. You have a process between your application and the network, which can be fed the appropriate TELNET commands to make the required connection. You can then communicate with an FTA device, just like you're currently communicating with an LTA device. The cost is an extra process per port.

I've got some sample code that does this, if you're interested.
A crucible of informative mistakes
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marsh_1
Honored Contributor

Re: Reverse Telnet TNA Device

alternatively you can spool the tna device to the old lat device.

Hal Kuff
Occasional Advisor

Re: Reverse Telnet TNA Device

Hi, great input (no pun)... basically this is a legacy application that is run from a command file by a vendor at login and then dials back a number tied to their account and sends product labels to a bar code printer conencted to a mode... low tech but has worked for 20 years... interested in 'spooling to the LTA from TNA'... that work?
marsh_1
Honored Contributor

Re: Reverse Telnet TNA Device

hi,

sorry meant spool the lta device to a telnetsym print queue set up in this instance to point to - /on:"10.10.10.10:2010" -.
but these were set lta devices known to our app going to decserver ports no modems involved, don't how your application does it.
you can try spooling direct to a tna device i got variable results when i tried it.

HTH
Volker Halle
Honored Contributor

Re: Reverse Telnet TNA Device

Hal,

did you check the $ TELNET/CREATE_SESSION command ? It is supposed to create a TNA device and map it to an IP-port on the DECserver.

Volker.
Volker Halle
Honored Contributor

Re: Reverse Telnet TNA Device

Hal,

consider to have a look at this thread:

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1096598

Volker.
Hakan Zanderau ( Anders
Trusted Contributor

Re: Reverse Telnet TNA Device

Maybe I'm sticking out my neck here......

If your application uses hardcoded LTAdevices.
Wouldn't a logical name take care of the redirection from LTA to TNA +

Create a TNA-device and remap the LTA-device

$ DEFINE/SYS LTA1: TNA1:

Hakan
Don't make it worse by guessing.........
marsh_1
Honored Contributor

Re: Reverse Telnet TNA Device

hal,

we did ours like this

$INIT/QUE/PROC=TCPIP$TELNETSYM/RETAIN=ERROR/RECORD_BLOCKING /SCHEDULE=NOSIZE/DEF=(noburst,nofeed,noflag,notrail) /ON:"'decserver_ip_host_name':'ip_port'" 'que_name'

$set dev 'lta_dev_name':/spooled='telnetsym_que

with these two tcp logicals set

$DEFINE/SYSTEM TCPIP$TELNETSYM_IDLE_TIMEOUT "0 00:00:30.00"
$DEFINE/SYSTEM TCPIP$TELNETSYM_RETRY_INTERVAL "0 00:00:30.00"

example tna device creation

$TELNET/CREATE_SESSION/TIMEOUT=(NOIDLE,RECONNECTION=0:0:30) 'ip_host_name' 'port' 'tna_device_number'

HTH