Maintaining NNCP

The care and feeding of an NNCP[1] installation.

NNCP needs little care, but it there are a few things that can help.

NNCP's administration page[2] is a good place to read about this. My Debian[3] packages do some of this for you, and provide examples for much of the rest as well.

Rotate the log file

NNCP has a log file, which by default is under the spool directory (`/var/spool/nncp` by default). This can be rotated by something like logrotate. I ship this example with Debian:

/var/spool/nncp/log
{
       rotate 14
       daily
       missingok
       notifempty
       compress
       delaycompress
       su nncp nncp
}

Clean up cruft

There are some files that NNCP creates that can be cleaned up using nncp-rm[4] beginning with NNCP version 8.7.2. I ship this example with Debian:

#!/bin/bash

for TYPE in part seen hdr area; do
        su nncp -s /bin/bash -c "nncp-rm -quiet -all -older 7d -$TYPE"
done

su nncp -s /bin/bash -c "nncp-rm -quiet -tmp -older 7d"

Cleaning up packets themselves

NNCP by default only removes packets under these circumstances:

• tx packets, when they have been transmitted (confirmation from nncp-call/caller/daemon, sent with nncp-xfer, or ACKed by nncp-ack)
• rx packets, when they have been *successfully* processed by nncp-toss

(See NNCP Concepts[5] for more on these ideas)

There are some circumstances in which packets could accumulate:

• rx packets that cause errors in processing. Examples could include requesting to run a command they're not allowed to, executing a command that exits with an error, trying to send a file to a machine that doesn't allow files from that node, and so forth. Some of these conditions may never be resolved, so a packet could linger forever.
• tx packets waiting to be picked up from a node that no longer exists or something.

Many people will never encounter these situations. The examples above do not actually delete any packets; they are non-destructive. I don't necessarily recommend automatic packet deletion in most cases. But if you really want to delete these automatically, you can:

su - nncp -s /bin/bash -c "/usr/local/bin/nncp-rm -all -rx -older 4d"
su - nncp -s /bin/bash -c "/usr/local/bin/nncp-rm -all -tx -older 10d"

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Links to this note

• NNCP[6]

NNCP lets you securely send files, or request remote execution, between systems. It uses asynchronous communication[7], so the source and destination need never be online simultaneously. NNCP can route requests via intermediate devices -- other NNCP nodes, USB sticks, tapes, radios, phones, cloud services, whatever -- leading to a network that is highly resilient and flexible. NNCP makes it much easier to communicate with devices that lack Internet connectivity, or have poor Internet.

More on www.complete.org

(c) 2022-2024 John Goerzen