Given that I don't know what IP subnet always comes from the ISPs, I'm curious as to why you included the 192.168.1.1 in the gateway4 and nameserver fields? Is there a way to properly determine what these should be when we don't know the lease value for eth(1|2|3)? I realize that I put those into my config above, but this is perhaps part of where I'm confused and part of the answer to your comment above...

@ylluminate I made some minor edits in my answer, based on slangasek's answer. I'm waiting for confirmation on the new .yaml.

just tested and this is getting closer (I suspect .10.1 needs to be assigned to an interface / route in some fashion that chooses eth1 or eth2 based on availability and priority?) Screenshot: share.getcloudapp.com/rRu9A4zj

@ylluminate Try ping -I eth0 1.1.1.1 and ping -I eth1 1.1.1.1 and ping -I eth2 1.1.1.1 and see which ones may respond, and which ones might not. Also make sure that .2 is valid for that network.

eth0 is complete loss. Both eth1 and eth2 reply correctly. This machine is isolated and only has ISP (eth1 & eth2) connections with eth0 (192.168.10.2) going out to a LAN so it shouldn't matter what IP is used here. It's simply that there is no .10.1 as far as I can tell since I thought this machine itself should / would be .10.1...

@ylluminate For eth0, there is no router/modem? If not, then how can it be the primary WAN? See if you can ping -I eth0 192.168.10.x, ping another device on the 192.168.10.x LAN. Only eth1 and eth2 have a router/modem?

Ugh, you're absolutely right. I had forgotten I had changed the diagram and thought I'd uploaded it - but had not. I've pushed an updated diagram into the original question now to hopefully resolve this. Sorry about that!

hello

hey there - obviously my original netplan yml didn't agree with the diagram

i had shown the 1st isp on eth0 on my diagram BUT it was eth1 on my yml... :S

so now they should be in agreement...

so, eth0 lan has no modem/router, only other IP devices?

??

right

eth0 is lan (you could pretend it goes to a switch, but in reality it just goes to another router that does more heavy lifting)

in the .yaml, if you remove routes/to/via/metric, and sudo neplan blah blah, can you then ping other devices on that lan?

let me check. i'll have to get over to my workstation where that's set up

ok

hmm, no. i have a workstation here set to 192.168.20.32 (no firewall) and i can't ping from ubuntu to it neither from it to ubuntu (192.168.20.1)

(i have this workstation set with an additional ip so it has both internet access + the ip of this other subnet)

oh hang tight - let me check something

that's a different subnet. let me ask... do devices on the 192.168.x.x require internet access?

i've been working on another machine as well here - yes

so yes, i have an archlinux system i'm doing the same thing with but via shorewall and it's on .20

so yes, with routes/to/via/metric removed it DOES ping

lol, sorry - i've been in such a rush here as i need to finish this today that i've been trying other options

well i can ping ubuntu -> windows

last question, I think... so eth1/2/3 EACH have there own router/modem/ISP?

but i cannot ping windows (.10.32) -> ubuntu (.10.1)

that is correct

eth1/2/3 all are diff ISPs

and sometimes only eth1 isp is on

so it's the primary and most important, but occasionally it goes down and thus 2 and/or 3 may be used

I think you need to draw a more detailed map, and explain in more detail the bigger picture, and any specifics. Let me go modify my .yaml based on some of the new details, and I'll ping you when it's done.

ok?

thanks very much

give me a few minutes then...

sure thing

oh, I forgot...

Do you really have any nameservers on the 192.168.10.x network?

not yet - i actually don't think i will put one on it

ah. I'll change my .yaml... but I may not have enough experience to do what you're asking... but I'll see if I can just get the basics going. Back in a few...

i have thought about it, but at this point i'm fine with just pushing cloudflare's 1.1.1.1 through and letting the receiving router (we'll say 192.168.10.2) handle dhcp, etc.

sure thing. this is just mostly a dumb isp multiplexer running on ubuntu 20.04 on a raspberry pi 3b+ for a small office that has internet trouble in a remote location

the problem i've had with netplan docs is that it hasn't been clear as to whether i should use a bridge, bonding or what you're doing now. it's really unfortunate that they don't include more examples on their site. different things i've read seem to point in various directions with netplan....

ok, my changes are (in)complete. Right now it's only set to work with eth0 and eth1. If that works, eth1 and eth2 might be easy... or the whole thing might require more difficult routing that I can't help with. slangsek is good at this stuff, if we can get his attention. Try my current .yaml and see what happens. Report back.

alright, so i'm hesitant to share this diagram on the main question due to the nature of some of the criticism i've seen from other folks on similar questions, but for your eyes only: p153.p0.n0.cdn.getcloudapp.com/items/YEu16qGw/more_details.png

wow, alright that works

at least with my eth1 set to wireless right now since i'm not testing dsl yet (not being actually onsite)

(wireless being iphone USB tether)

now let me test a little more

great! I'm not 100% about eth2 and eth3... I've amended my message to slangasek. But I'm going to have to bail out now, before I embarrass myself.

Please do keep me posted though.

well sorry - i spoke too soon

internet works fine on the actual ubuntu system now and the test system pings to 192.168.10.1

but doesn't get out to 1.1.1.1

it won't, as it has no knowledge of 1.1.1.1

only whatever nameservers dhcp supplies

oh, maybe I still misunderstand...

the test system net config: p153.p0.n0.cdn.getcloudapp.com/items/eDu6bWLW/…

so i statically set the test system to be .10.32 as you see with .10.1 as gateway and the dns to 1.1.1.1

I can't wrap my head around all of this. Sorry.

Out of my experience range.

lol, np. thanks so much for your time. i think it's a routing issue still

yes

bye for now then.

catch you later and will keep you posted

it's surprising that this info is not more readily available / documented for netplan :'(

thanks... and I'd consider putting up that latest diagram.

i updated it with that image and an update note while also commenting on slangasek's answer.