Set up transmission server:
===========================
1. First, install packages on Ubuntu by:
sudo apt install transmission-cli transmission-common transmission-daemon

2. stop tramsmission (so you can save changes in the config file) by:
sudo systemctl stop transmission-daemon

3. edit this file:
sudo nano /var/lib/transmission-daemon/info/settings.json
and make these changes:
change  "download-dir" & "incomplete-dir" to "/opt/RD/UNAS/.Torrent_hub/downloads"
change "rpc-username" to a different one from default
change "rpc-whitelist" to "127.0.0.1,192.168.*.*,10.8.*.*"
change "rpc-password" to wanted password

save using ctrl + x

4. add proper user gorups by:
sudo usermod -a -G debian-transmission owner (replace owner with your user)
sudo chgrp -R debian-transmission /opt/RD/UNAS/.Torrent_hub
sudo chmod -R 770 /opt/RD/UNAS/.Torrent_hub
sudo chown debian-transmission:debian-transmission -R /opt/RD/UNAS/.Torrent_hub
sudo adduser debian-transmission users
*Make sure that directories before .Torrent_hub have access permission so not just the owner, but group and others can view & modify content. such as /opt/RD/UNAS/. This can be done by bringing up properties for a directory in KDE's Dolphin file manager.

5. start transmission by:
sudo systemctl start transmission-daemon

6. can get to transmission web page and login by:
http://branden-g.ca:9091/transmission/web/

7. Sucess!

Note for ubuntu torrents:
The error for requested-download-is-not-authorized-for-use-with-this-tracker when downloading a ubuntu iso (such as from the old-releases mirror) is due to the tracker host not updated to new location. can no longer use that tracker.

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Sources:
https://www.addictivetips.com/ubuntu-linux-tips/set-up-transmission-bittorrent-server-on-linux/
https://askubuntu.com/questions/869046/transmission-daemon-ignoring-settings-json#890721
https://forum.transmissionbt.com/viewtopic.php?t=13725
https://askubuntu.com/questions/1456578/ubuntu-22-04-2-requested-download-is-not-authorized-for-use-with-this-tracker
https://askubuntu.com/questions/221081/permission-denied-when-downloading-with-transmission-daemon#221096
https://raspberrypi.stackexchange.com/questions/4378/transmission-permission-denied-on-usb-disk
https://askubuntu.com/questions/221081/permission-denied-when-downloading-with-transmission-daemon
https://askubuntu.com/questions/1436688/transmission-daemon-folder-permissions-issue
https://askubuntu.com/questions/1146034/what-is-the-meaning-of-drwxrwxr-x-and-drwxr-xr-x
https://superuser.com/questions/1571057/how-can-i-chmod-a-directory-to-drwxr-sr-x
https://askubuntu.com/questions/915741/permission-denied-when-downloading-with-transmission
https://askubuntu.com/questions/522307/transmission-started-with-a-permission-denied-now-it-wont-even-run
https://askubuntu.com/questions/268606/transmission-daemon-permission-denied-even-if-debian-transmission-has-root-grou

Date in Vivaldi: September 28th 2023.