Connect Ubuntu PC Directly to DUET EtherNet Without a Router?

Schild0r · 9 Apr 2021, 14:58

I find myself having a related problem:
I want to use my Duet 3 in standalone mode but hook it to the network using a direct connection. Not to a Windows or Ubuntu PC but instead to a raspberry pi running raspbian (no, I don't want to run the Duet 3 in SBC mode for reasons...).

I already configured the raspi to work as wired router after this tutorial. It even has a DHCP server and I can connect my PC to the pi directly and can access the internet through this without any problems.

But when I connect the Duet 3 to it I can not access the DWC by
either entering the ip address the Duet gets assigned from the DHCP server on the raspi (which I can read from YAT)
or entering the statically assigned IP from the raspberry pi ethernet adapter
(there is conflicting information on which one you should use here in the forum and here in the documentation)
subnet masks are all matching 255.255.255.0

I have the feeling that there are the right people here in this thread that can help me... I don't know what else I should try rn.

BTW if I connect the Duet 3 directly to the ISP router I can access DWC no problem entering the IP address I get from M552 in YAT.

------ probably unneccessary information ------
At first I set up the raspi using the same subnet as in the above mentioned tutorial 192.168.100.xx (192.168.100.1 for the raspi eth0 and 192.168.100.50-240 as DHCP range with the Duet 3 then being assigned 192.168.100.50) but noticed that 192.168.100.1 actually connected me to the setup page of my ISP router. I then switched to the 192.168.101.xx subnet and connecting my PC to the internet through this still works but I still can't connect to any IP address (neither the .1 of the raspi nor the .50 of the Duet 3 which again I checked in YAT)

I also already disabled the DHCP server on the raspi and assigned a static IP address to the Duet 3 but that made no difference
------ end of probably unneccessary information ------

dc42 · 9 Apr 2021, 15:12

@schild0r , have you tried using a crossover cable? The Duet Ethernet port doesn't auto-switch, and I don't know whether the RPi Ethernet port does.

Schild0r · 9 Apr 2021, 15:37

@dc42 yes I tried patch cables and crossover cables

Schild0r · 9 Apr 2021, 16:52

I noticed that even if the PC can connect to the internet through the direct connection with the raspi, I cannot ping it with another device from my wifi network. I think if I can manage to get this working I will have my solution.

stuartofmt · 9 Apr 2021, 17:02

@schild0r

I happened across this and have wrestled with such problems mightily in the past (usually on a customer site just prior to a presentation).

If I missed this suggestion in the thread - I apologies but ....

When trying to connect PC-PC(or Duet) 1:1 via an ethernet cable -- its best to make sure than neither has it's wireless connection active. That way - you are trouble shooting only one problem (not a potential combination of interactions).

Also - turning off both firewalls until you get it working

Hope this helps.

Schild0r · 9 Apr 2021, 17:47

@stuartofmt said in Connect Ubuntu PC Directly to DUET EtherNet Without a Router?:

If I missed this suggestion in the thread - I apologies but ....

When trying to connect PC-PC(or Duet) 1:1 via an ethernet cable -- its best to make sure than neither has it's wireless connection active. That way - you are trouble shooting only one problem (not a potential combination of interactions).

well the problem is that I am not troubleshooting the wired part of the PC-PC (RPI-Duet) connection but the wireless part of the PC: (:Router:) :RPI-Duet connection (wireless being the colons)

Also - turning off both firewalls until you get it working

Hope this helps.

that did not help either unfortunately

stuartofmt · 9 Apr 2021, 18:24

@schild0r said in Connect Ubuntu PC Directly to DUET EtherNet Without a Router?:

well the problem is that I am not troubleshooting the wired part of the PC-PC (RPI-Duet) connection but the wireless part of the PC: (:Router:) :RPI-Duet connection (wireless being the colons)

Ah - OK. So the dash - between RPI and Duet is wired and the rest is wireless. In other words you want to bridge the ethernet to wlan on the Pi.
I've done that in the past but cannot remember all the ins-and-outs but it was somewhat convoluted (dnsmasq, iptables and etc.). From memory - the next time I had to do it - I found a longer ethernet cable and went straight to the router

This looks like it may be of help:

https://www.instructables.com/Share-WiFi-With-Ethernet-Port-on-a-Raspberry-Pi/

Good Luck.

Schild0r · 9 Apr 2021, 20:12

@stuartofmt after asking another friend I ended up with a different tutorial that did the same thing I already did only a completely different way (I honestly have no clue what the script does I just copied to the pie, but it keeps the connected devices in the same subnet) and it works. I think your link may have also helped but this was a 3 minute solution.

Schild0r · 9 Apr 2021, 20:27

@dc42 said in Connect Ubuntu PC Directly to DUET EtherNet Without a Router?:

The Duet Ethernet port doesn't auto-switch, and I don't know whether the RPi Ethernet port does.

FYI: I am using a RPi 4 B and it looks like it does auto switch. It's now working and I can use either cable

stuartofmt · 9 Apr 2021, 22:46

@schild0r said in Connect Ubuntu PC Directly to DUET EtherNet Without a Router?:

I ended up with a different tutorial

I'm always amazed by the number of alternative packages to do "the same thing" along with instructions that sometimes work and sometimes don't. That tutorial takes a slightly different approach but better still WORKED FIRST TIME !!

Congrats and thanks for posting the link.