Telnet Clarification

stuartofmt

I'm trying to get telnet to work as part of an experiment I'm doing but having no luck.

I've looked at this post:
https://forum.duet3d.com/topic/27396/basic-telnet-connection-help?_=1743333389705

I cannot get the python code to reflect the messages in M118.

I'm using SBC Bookworm with 3.6.0-rc.1

Here are some questions:

ON SBC: Does Duet Firmware implement its own telnet server or does it rely on the OS (telnetd)?

If telnetd is not running - I get a connection refused message. If telnetd is running connection succeeds but I do not see the output from M118 P4 S"Message"

Depending on the answer above - what does M586 P2 S1 actually do? Does it start a duet firmware telnet server? Does it enable / block M586 P2

I've seen a suggestion of using Putty to confirm telnet messages are being sent. Connection to the SBC using telnet on Putty does not show the M118 messages either.

chrishamm

@stuartofmt I wouldn't recommend Telnet in SBC mode, it's insecure. In SBC mode, the DuetPiManagementPlugin only tries to activate the Telnet server via xinetd.

If you need a TCP port to send/receive G-code data, you'll have to write a plugin for SBC mode or wrap it around the HTTP API.

PS: It might actually suffice to forward a TCP port to the CodeStream/CodeConsole application in /opt/dsf/bin. Those utilities use the Telnet G-code channel by default.

stuartofmt

@chrishamm

Thx. I understand all the caveats on Telnet.

I started off thinking about using it send a (local to the SBC) message to a standalone telnet listener that then made HTTP calls. I.e. implementing an HTTP get or post to an arbitrary url (Missing from M118). Fire-and-forget.

Upon reflection, ExecOnMcode in conjunction with curl will do the trick (passing the url as an argument).