[SOLVED] serial console connection

[d3pr3cat3d]

I am trying to get the serial console to function. I have enabled it as secondary console, set the speed as 115200, and have set " Use USB-based serial ports " as enabled.

I then have have joined two USB to serial converter (tripp-lite u209-000-r) with a null modem (https://www.amazon.com/dp/B075XGRLXW/ref=cm_sw_em_r_mt_dp_AH3V8N07GZY398GQJYQA?_encoding=UTF8&psc=1) in the middle. This should work correct?

I my Linux system I then type:

Code Select Expand

# minicom -b 115200 -D /dev/ttyUSB0

I press the enter key a few times but only have a blank screen.  :(

from my Linux host dmesg shows.

Code Select Expand

[596342.276400] usb 1-2: pl2303 converter now attached to ttyUSB0

dmesg form the OPNsense firewall

Code Select Expand

ugen0.4: <Prolific Technology Inc. USB-Serial Controller D> at usbus0
uplcom0 on uhub0
uplcom0: <Prolific Technology Inc. USB-Serial Controller D, class 0/0, rev 1.10/3.00, addr 7> on usbus0

OPNsense /etc/ttys shows:

Code Select Expand

# Serial terminals
# The 'dialup' keyword identifies dialin lines to login, fingerd etc.
ttyU0 "/usr/libexec/getty 3wire.115200" vt100 onifconsole secure
ttyU1 "/usr/libexec/getty 3wire.115200" vt100 onifconsole secure
ttyU2 "/usr/libexec/getty 3wire.115200" vt100 onifconsole secure
ttyU3 "/usr/libexec/getty 3wire.115200" vt100 onifconsole secure
# Dumb console
dcons "/usr/libexec/getty std.9600" vt100 off secure

This is the motherboard in use on the OPNsense firewall and I am running v20.7.2
https://www.asrock.com/MB/Intel/H470M-ITXac/index.asp

Thank you.

[franco]

Can you print the output of:

# ls /dev/ttyU*

Maybe init needs a bit of a jolt if you plug the USB into a running system:

# kill -HUP 1


Cheers,
Franco

[d3pr3cat3d]

Thank you franco.

Code Select Expand


# ls /dev/ttyU*
/dev/ttyU0 /dev/ttyU0.init /dev/ttyU0.lock

I have unplugged the USB serial converter and plugged it back on both systems and ran

# kill -HUP 1

on both systems too.  ;)


There was no change to the issue.

Here are the minicom settings on the Linux system

Code Select Expand

+-----------------------------------------------------------------------+                           
| A -    Serial Device      : /dev/ttyUSB0                              |                           
| B - Lockfile Location     : /var/run                                  |                           
| C -   Callin Program      :                                           |                           
| D -  Callout Program      :                                           |                           
| E -    Bps/Par/Bits       : 115200 8N1                                |                           
| F - Hardware Flow Control : No                                        |                           
| G - Software Flow Control : No                                        |                           
| H -     RS485 Enable      : No                                        |                           
| I -   RS485 Rts On Send   : No                                        |                           
| J -  RS485 Rts After Send : No                                        |                           
| K -  RS485 Rx During Tx   : No                                        |                           
| L -  RS485 Terminate Bus  : No                                        |                           
| M - RS485 Delay Rts Before: 0                                         |                           
| N - RS485 Delay Rts After : 0                                         |                           
|                                                                       |                           
|    Change which setting?         


Update
To test the cables I shorted out pins 2 and 3 per:
https://forum.opnsense.org/index.php?topic=15417.msg85417#msg85417
and reference:
https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000YFtECAW&l=en-US

And I was able to see the text I typed, so the cables are not the issue.

Update part 2
I tested on the loopback on the firewall too

Code Select Expand

# cu -l /dev/ttyU0
Connected
la;as;dfas

[d3pr3cat3d]

I got this working somewhat, I have to change "onifconsole" to "on".

change from:

Code Select Expand

ttyU0   "/usr/libexec/getty 3wire.115200"       vt100   onifconsole secure

change to:

Code Select Expand

ttyU0   "/usr/libexec/getty 3wire.115200"       vt100   on secure

So now I have two questions.

How do I make this persistent so that it survive a reboot?

What does "onifconsole" do vs. "on"?

I actually found another setting to add to the confusion, "onifexists".

[d3pr3cat3d]

Any thought on how to make this persistent across reboots?

[d3pr3cat3d]

How can I make this persistent?

If I change the line that has "ttyU0" in /etc/ttys from "onifconsole" to "on", it works great. But is will not stay if the system is rebooted.

change from:

Code Select Expand

ttyU0   "/usr/libexec/getty 3wire.115200"       vt100   onifconsole secure

to this:

Code Select Expand

ttyU0   "/usr/libexec/getty 3wire.115200"       vt100   on secure

and then restart init:

Code Select Expand

# kill -HUP 1

You can now see that the console is running:

Code Select Expand

# ps | grep getty
98163  0  R+   0:00.00 grep getty
95361 U0  Is+  0:00.00 /usr/libexec/getty 3wire.115200 ttyU0

[franco]

Trading a fix for a ticket https://github.com/opnsense/core/issues/new?assignees=&labels=&template=feature_request.md&title=

I don't mind pinning USB console option to "on" instead of "onifconsole".


Cheers,
Franco

[d3pr3cat3d]

Thank you Franco, a ticket has been submitted.

https://github.com/opnsense/core/issues/4849

[silke61]

Was the solution removed in the meantime? I also had the problem that I could not connect via serial console and in /etc/ttys there was again "onifconsole" instead of "on". After changing it to "on" and a "kill -HUP 1" it worked as it should.

This is using xterm.js as Proxmox console, I don't know how it behaves with a physical console, I have everything virtualized.

[franco]

There was https://github.com/opnsense/core/commit/8e80bf6c2007c1 but it doesn't change the behaviour as far as I can tell. The code is still the same.


Cheers,
Franco

[silke61]

Then perhaps it is because I do not use a USB based serial console. My guess is that Proxmox emulates a physical serial console without USB and the original fix solved only part of the problem?
But since not everyone has problems connecting perhaps it is USB based after all and I just didn't know and have to select the USB checkbox. But then a hint in the documentation would be helpful: Either mention Proxmox explicitly or give a more general advice to try the checkbox in case of connection problems.

I really don't know what is happening, only that the change to "on" solved the problem and perhaps it helps others.

[franco]

I'd agree that USB serial consoles are fringe and reserved to actual serial over USB bus and definitely not emulated by Proxmox.

If the serial isn't working the settings for it are likely wrong.  For VMs one mostly starts with a VGA image which doesn't have serial enabled.


Cheers,
Franco

[silke61]

For VMs one mostly starts with a VGA image which doesn't have serial enabled.

That's why I enabled it after installation. The standard VGA based console in Proxmox has a few disadvantages, e.g. it doesn't support cut & paste (at least not easily), that is why I used the serial based xterm.js console. As I said, it works, but only after I changed 'onifconsole' to 'on'. Is there any reason not to always set it to 'on' when enabled?
If there are good reasons it is fine with me since I found a solution, it is just one more thing to remember for a possible new install. (And if I miss it, a web search will hopefully lead me to this post to remind me)

Thanks for all your great work!
Silke

[franco]

It was never needed and I recall no reports that it would have. It's the FreeBSD default we try to follow.

If it fixes your issue I'd appreciate a GitHub ticket and I can see how to offer this. It's not great to micro-manage this but if it fixes a real world issue that's ok.

https://github.com/opnsense/core/issues/new?template=feature_request.md


Cheers,
Franco

[silke61]

Now I am totally perplexed. After your answer I did some more research and found the info that onifconsole only works when in /boot/loader.conf comconsole is set before vidconsole in the console parameter. So I changed it, also set /etc/ttys back to onifconsole and rebooted but after the reboot loader.conf was back to the old sequence, onifconsole was still set but now the serial console worked !?! I promise I tried dozens of times before and it definitely did not work with these very settings.

But since it now works with onifconsole I will not write a feature request. Whatever happend in my instace I don't think OPNsense is at fault.

Thanks for your responsiveness and sorry for the noise
Silke