2024-06-28 Connecting the laptop to the server via NNCP
=======================================================

First, install the nncp package on both systems. In addition to that,
install the openbsd-inetd package on the server. (In the following
passages, I'm connected as root to the server.)

Generate new configs on the systems that are missing /etc/nncp.hjson.

    nncp-cfgnew > /etc/nncp.hjson
    chown nncp:nncp /etc/nncp.hjson
    chmod 660 /etc/nncp.hjson

Examine the file using a text editor. Each system needs to know the
public keys of the other.

So, on the laptop, I need to add to add the public keys of the server.
I also want to specify that I'm going to call the node on a regular
basis and that files sent to me from that node should be saved in my
"incoming" directory. I also want to accept mail.

        sibirocobombus: {
          id:       ...
          exchpub:  ...
          signpub:  ...
          noisepub: ...
          incoming: "/home/alex/incoming/sibirocobombus"
          exec: {
            sendmail: ["/usr/sbin/sendmail"]
          }
          addrs: {
            internet: "alexschroeder.ch:5400"
          }
          calls: [
            {
              cron: "12 * * * *"
            }
          ]
        }

And on the server, I need to add the public keys of the laptop. I also
want to save incoming files from the laptop. And I want to accept
mail.

        melanobombus: {
          id:       ...
          exchpub:  ...
          signpub:  ...
          noisepub: ...
          incoming: "/home/alex/incoming"
          exec: {
            sendmail: ["/usr/sbin/sendmail"]
          }
        }

Note how the laptop calls the server but the server does not call the
laptop!

Let's make sure those directories exist:

    mkdir ~/incoming
    ssh sibirocobombus mkdir incoming

Let's create a file and send it from the laptop to the server using
nncp-file:

    echo Hello > hello.txt
    sudo -u nncp nncp-file hello.txt sibirocobombus:

Check the log using nncp-log:

    nncp-log | tail -n 1
    2024-06-28T21:36:02Z File hello.txt (282 B) is sent to sibirocobombus:hello.txt

Let's connect to the server and check:

    ssh sibirocobombus ls incoming

Nothing has arrived!

Let's call the server using nncp-call:

    sudo -u nncp nncp-call sibirocobombus
    2024-06-28T22:07:36Z ERROR Calling sibirocobombus (alexschroeder.ch:5400): dial tcp [2a02:418:6a04:178:209:50:237:1]:5400: connect: connection refused

Oops. It's not running? That's right, I need to run nncp-daemon on
the server side.

Add the following to /etc/inetd.conf on the server to accept NNCP
connections on port 5400:

    5400	stream	tcp	nowait	nncp	/usr/bin/nncp-daemon	nncp-daemon -quiet -ucspi

Reload it:

    systemctl reload openbsd-inetd

Try again on the laptop:

    sudo -u nncp nncp-call sibirocobombus
    2024-06-28T22:14:13Z We have got for sibirocobombus: 1 packets, 486 B
    2024-06-28T22:14:13Z ERROR SP with sibirocobombus (nice MAX): reading: EOF
    2024-06-28T22:14:13Z ERROR Connection to sibirocobombus (alexschroeder.ch:5400): EOF

Back to the server:

    nncp-log
    2024-06-28T22:15:25Z ERROR SP nice MAX: waiting for first message: unknown peer: ...
    2024-06-28T22:15:25Z Connected to unknown

Strange! That id listed there matches my laptop's noisepub. Checking
the /etc/nncp.hjson on the server again, I see that I had pasted the
wrong pubkeys… 🤦 Fix that and try again…

    sudo -u nncp nncp-call sibirocobombus
    2024-06-28T22:19:31Z We have got for sibirocobombus: 1 packets, 486 B
    2024-06-28T22:19:31Z Connection to sibirocobombus (alexschroeder.ch:5400)
    2024-06-28T22:19:31Z Tx QAROTFMX25ZPQOT5..I6JKH75EC2DMSSZQ 486 B/486 B 100% (0 B/sec)
    2024-06-28T22:19:31Z Packet QAROTFMX25ZPQOT5DEQQC7JE7EN3UD2FZIJNI6JKH75EC2DMSSZQ is sent
    2024-06-28T22:19:42Z Finished call with sibirocobombus (0:0:11): 32 KiB received (32 KiB/sec), 33 KiB transferred (33 KiB/sec)

Looking good! Check for the file on the server:

    ssh sibirocobombus ls incoming

It's not there!

Let's investigate on the server:

    nncp-log
    2024-06-28T22:19:31Z Packet QAROTFMX25ZPQOT5DEQQC7JE7EN3UD2FZIJNI6JKH75EC2DMSSZQ (486 B) (nice B): 0%
    2024-06-28T22:19:31Z melanobombus has got for us: 1 packets, 486 B
    2024-06-28T22:19:31Z Connection with melanobombus (PIPE)
    2024-06-28T22:19:31Z Got packet QAROTFMX25ZPQOT5DEQQC7JE7EN3UD2FZIJNI6JKH75EC2DMSSZQ 100% (486 B / 486 B): done
    2024-06-28T22:19:42Z Finished call with melanobombus (0:0:11): 33 KiB received (33 KiB/sec), 32 KiB transferred (32 KiB/sec)

This looks good, so we have the packet! And we can confirm this using
nncp-stat:

    nncp-stat
    melanobombus
    	nice:   B | Rx:      486 B,   1 pkts | Tx:        0 B,   0 pkts
    self

What needs to happen now is "tossing" using nncp-toss. This is,
"processing" the packet and thereby delivering it.

    sudo -u nncp nncp-toss
    2024-06-28T22:24:28Z ERROR Tossing file melanobombus/QAROTFMX25ZPQOT5DEQQC7JE7EN3UD2FZIJNI6JKH75EC2DMSSZQ (6 B): hello.txt: mktemp: open /home/alex/incoming/nncpfile17dd4b56c39f64d4: permission denied

That's right, the incoming file should be writable by more people…

    chgrp nncp /home/alex/incoming
    chmod g+w /home/alex/incoming

Try again!

    sudo -u nncp nncp-toss
    2024-06-28T22:26:35Z Rx file QAROTFMX25ZPQOT5..I6JKH75EC2DMSSZQ 6 B/6 B 100% (0 B/sec)
    2024-06-28T22:26:36Z Got file hello.txt (6 B) from melanobombus

It worked:

    ls -l /home/alex/incoming/
    total 4
    -rw-r--r-- 1 nncp nncp 6 29. Jun 00:26 hello.txt
    
    cat /home/alex/incoming/hello.txt 
    Hello

🥳

I need to think about admin issues, clearly.

I need to set up regular nncp-call on the laptop; I need to set up
regular nncp-toss on the server.

It would be nice to switch from inetd to systemd perhaps? Surely
they have written a replacement for it. They have written replacements
for everything! 😬

Next up, sending email back and forth!

​#Administration #NNCP ​#NNCP