( Solved ) Odd sftp issue

[Danbor]

So, I've got a small home setup using a ISP ( comcast ) provided router. Two computers, both running Mint 21.3 and a printer. Ok, I've got two more, but the laptop is shut down right now and the Mint/ widows dual boot HP is gathering dust in the closet.
At any rate, all boxes are running mint 21.3. All have Openssh server, Openssh client and Openssh-sftp server installed. I'm also running Nordvpn on all boxes. I have them networked with the command "sftp://username@IPadress/" This setup has been in place for about a year now with few glitches. However, of late, and I can't recall when it started, I get this odd seeming issue. Mind you, the laptop and the HP are both powered down and out of the loop at present so I don't know if the issue extends to them or not. Anyway, here's the issue.
I start the day powering both computers. On box b, I open file manager and click on the link for box a. This results in a "host could not be found" error message. So, I close file manager and wander into the other room to computer a. From computer a, open file manager, click the link for computer b and, viola, there's all the files for computer b. Now I wander back to computer b, open file manager, click the link for computer a, and then it finds computer a and everything is fine.
Until one or the other of them drops into suspend. When awoken, we do that same shuffle again to restore connectivity.
So, what am I suddenly doing wrong?

 

[Condobloke]

Turn suspend off

Turn screensaver On.

It may not be you doing something wrong....and update somewhere may have caused this to change

 

[Condobloke]

have you rebooted the router?....just a late thought.

 

[Danbor]

I tried resetting the router. No change.
Screen saver is already on. I could turn off suspend, but doing so doesn't tell me what the issue is. I can live with the odd behavior, I just want to know what the actual problem is and thought perhaps one of you learned folks have ran into this problem before.
Thanks for the tips!

 

[Condobloke]

There is a good chance that the issue is suspend.

Linux users have always had varied experiences with suspend. Myself included. I will never use it.

 

[Danbor]

Well, apparently the issue has evolved rather than resolved. I disabled suspend on both boxes and rebooted with no effect.
However, Just to check, I fired up the laptop, Same thing.Here's where it now stands vis a vis connectivity on my little home set up.
All 3 computers running 21.3. On all 3, advanced network settings and wireguard settings are the same. All firewalls disabled. All three IP addresses start the same, 10.0.0.XXX/24 as does the printer.
10.0.0.131 can ping 10.0.0.18, 10.0.0.164 and 10.0.0.252 ( printer ).
18 can ping 164 and 252 but not 131.
164 can ping 18 and 252 but not 131.
252 will accept and run print commands from all 3 computers.
Where do I go next?

 

[GatorsFan]

Might want to have a look at this thread - https://serverfault.com/questions/922024/sftp-through-multiple-computers

 

[Danbor]

Hi GatorsFan. And thanks for the tip.
I checked out the suggested thread. That may be the way I have to wind up going but I need to learn a little more. For one, in the example commands given, is the word "localhost" meant to be entered verbatim or should an IP address be substituted? Same for the computer names, IP addy or something else.
Also, if I follow it correctly, computerA must be present at all times or the whole thing is kaput. Not desirable. There is no server as such, just 3 peers.
Will this configuration interfere with Nord VPN or Wireguard?
Does this setup work with the file manager? For me, the CLI is for fixing a problem. Day to day tasks are what the GUI was invented for, and what I prefer to use.
And, the main question, why would this need to be done now when it's worked flawlessly for over a year without it?

 

[dos2unix]

is the word "localhost" meant to be entered verbatim or should an IP address be substituted?

Usually you can type in "localhost". The IP address for localhost is always 127.0.0.1 on every computer.

Also, if I follow it correctly, computerA must be present at all times or the whole thing is kaput. Not desirable. There is no server as such, just 3 peers

Well, scp/sftp is a service. So in reality, you have 3 servers. All 3 don't have to be up at the same time. Just the two you are transferring files between.

Does this setup work with the file manager? For me, the CLI is for fixing a problem. Day to day tasks are what the GUI was invented for, and what I prefer to use.

Typically not the file manager. But there are sftp/scp GUI clients.

For me, the CLI is for fixing a problem. Day to day tasks are what the GUI was invented for, and what I prefer to use.

There are some things that are easier to do from the command line. We have over 6,000 computers in a data center, and none of them have a GUI, or a mouse or monitor screen. Everything is done via ssh/command line.

 

[GatorsFan]

@dos2unix pretty much said it all - not much more I can add to it

 

[Danbor]

Thanks for the input guys. I'll keep gnawing at the issue.
I do understand that some things are easier done from the CLI. However, I'm not working on a network with 6000 computers. Just 3 or 4, all with just one user.
In fact, all four computers are set up as close to exactly the same as I could get them, even to the password, it's the same on all of them. Which computer I use depends only on what room I happen to be sitting in at the time.
So, with all that said, I'm still left with one of the 3 that behaves differently than the other 2. I need to figure out what is causing that difference and how to correct it.
The setup I have has worked fine for a year without setting up or installing anything. Even the initial sftp connections were made from the Nemo window. Make the connection, add it to favorites and rename it something other than an IP address. Done.

 

[Danbor]

Update. I figured it out!
I found the command "ip addr show" and ran it on the problem machine. Somehow, and I don't know how, 10.0.0.131 has been changed to 10.0.0.132.
After that, all I had to do was go to the other computers and run sftp://[email protected]/ in Nemo on each one, add it to bookmarks and rename it. Back in business.

 

[Condobloke]

well done !

It's always the simple things !

 

[f33dm3bits]

Update. I figured it out!
I found the command "ip addr show" and ran it on the problem machine. Somehow, and I don't know how, 10.0.0.131 has been changed to 10.0.0.132.

Details matter! Glad you got it working! The only thing I can think of is that your system is setup to use dhcp so that it automatically receives the network configuration from your router and those are dynamic meaning they can change.