TFTP PNM File Retrieval Setup (Config Menu)¶

This example shows how to configure TFTP-based PNM file retrieval using the interactive config-menu helper. In this scenario, localhost is selected as the TFTP host, which means the TFTP server and PyPNM are running on the same box. PyPNM will still use the TFTP protocol to download PNM files for analysis.

The remote_dir is the directory on the TFTP server where PNM files are stored and served. Leaving it empty ("") uses the TFTP server's default root (often something like /srv/tftp, depending on your server configuration).

(.env) PyPNM$ config-menu

PyPNM System Configuration Menu
================================
Select an option:
  1) Edit FastApiRequestDefault
  2) Edit SNMP
  3) Edit PnmBulkDataTransfer
  4) Edit PnmFileRetrieval (retrieval_method only)
  5) Edit Logging
  6) Edit TestMode
  7) Run PnmFileRetrieval Setup (directory initialization)
  q) Quit
Enter selection: 7

Running: PyPNM/tools/pnm/pnm_file_retrieval_setup.py

INFO PnmFileRetrievalConfigurator: Using configuration file: PyPNM/src/pypnm/settings/system.json
INFO PnmFileRetrievalConfigurator: Created backup: PyPNM/src/pypnm/settings/system.bak.1765155200.json

Select PNM File Retrieval Method:
  1) local  - Copy from local src_dir
  2) tftp   - Download from TFTP server
  3) sftp   - Download from SFTP server
  q) Quit   - Exit without changes

Enter choice [1-4 or q to quit]: 2
INFO PnmFileRetrievalConfigurator: Selected retrieval method: tftp
Enter TFTP host [localhost]:
Enter TFTP port for localhost [69]:
Enter TFTP timeout seconds [5]:
Enter TFTP remote_dir []:
INFO PnmFileRetrievalConfigurator: Configured TFTP host=localhost port=69 remote_dir=
INFO PnmFileRetrievalConfigurator: PNM file retrieval configuration complete.

Script completed successfully.


PyPNM System Configuration Menu
================================
Select an option:
  1) Edit FastApiRequestDefault
  2) Edit SNMP
  3) Edit PnmBulkDataTransfer
  4) Edit PnmFileRetrieval (retrieval_method only)
  5) Edit Logging
  6) Edit TestMode
  7) Run PnmFileRetrieval Setup (directory initialization)
  q) Quit
Enter selection: q
Exiting System Configuration Menu.
(.env) PyPNM$

If PNM file retrieval fails with TFTP errors (for example, TFTP_PNM_FILE_FETCH_ERROR in the logs), verify:

The TFTP service is running on localhost and listening on UDP port 69.

Note: macOS includes a TFTP client but does not ship a native TFTP server. Use a third-party daemon if you need a local TFTP server on macOS. 2. The TFTP server is allowed to serve files (download) as well as accept uploads from the cable modem. Some configurations are upload-only. 3. The TFTP root or remote_dir actually contains the PNM files that the CM is writing. 4. Local firewall rules (or SELinux/AppArmor) are not blocking TFTP traffic between the CM and the PyPNM host, or between PyPNM and localhost itself.

Quick TFTP Health Check On Ubuntu (localhost)¶

The following steps assume a typical Ubuntu environment where tftpd-hpa is used and the TFTP root is /srv/tftp. Adjust paths if your configuration differs.

Install the TFTP server (if not already installed):

sudo apt update
sudo apt install -y tftpd-hpa

Check that the TFTP service is running:

systemctl status tftpd-hpa

Look for active (running). If it is not running, start it:

sudo systemctl start tftpd-hpa
sudo systemctl enable tftpd-hpa

Confirm the TFTP root directory:

sudo cat /etc/default/tftpd-hpa

 (.env) PyPNM$ sudo cat /etc/default/tftpd-hpa
 [sudo] password for dev01: 
 # /etc/default/tftpd-hpa

 TFTP_USERNAME="tftp"
 TFTP_DIRECTORY="/srv/tftp"
 TFTP_ADDRESS=":69"
 TFTP_OPTIONS="--secure --create"

Check the TFTP_DIRECTORY line. This directory must match what you expect for remote_dir (or be consistent with leaving remote_dir empty when it points to the server root). This is where the CM will write PNM files and where PyPNM will try to download them from.

Create a small test file in the TFTP directory (example assumes /srv/tftp):

echo "pypnm-tftp-test" | sudo tee /srv/tftp/pypnm-test.txt
sudo chmod 644 /srv/tftp/pypnm-test.txt

Install a TFTP client and test a download from localhost:

sudo apt install -y tftp
cd /tmp

tftp localhost
get pypnm-test.txt
quit

After the command, verify the file:

cat /tmp/pypnm-test.txt

You should see the contents pypnm-tftp-test. If this works, the TFTP server is able to serve files on localhost, which is the same path PyPNM will use when host=localhost and method=tftp are configured.

If the test fails, re-check:
TFTP service status (systemctl status tftpd-hpa)
The configured TFTP_DIRECTORY vs the directory where you put the file
Local firewall rules (for example, with UFW):
```
sudo ufw status
sudo ufw allow 69/udp
```

Once the manual TFTP test succeeds, PyPNM should be able to retrieve PNM files from the same TFTP root/remote_dir.