When trying to access transmission from web-browswer i got the message :
403: Forbidden
Unauthorized IP Address.
Either disable the IP address whitelist or add your address to it.
If you're editing settings.json, see the 'rpc-whitelist' and 'rpc-whitelist-enabled' entries.
If you're still using ACLs, use a whitelist instead. See the transmission-daemon manpage for details.
I setup whitelist before and it was working fine. So, it is not setting.json issue.
I check the log file:
root@ubuntu:~# less /var/log/syslog | grep trans
Jul 25 12:16:48 ubuntu transmission-daemon[26035]: [2017-07-25 12:16:48.151] Couldn't save temporary file "/home/debian-transmission/.config/transmission-daemon/settings.json.tmp.0uKjqQ": No such file or directory (variant.c:1280)
Jul 25 12:16:48 ubuntu transmission-daemon[26035]: Closing transmission session... done.
Jul 25 12:16:49 ubuntu transmission-daemon[26365]: [2017-07-25 12:16:49.422] Couldn't create "/home/debian-transmission": Permission denied (file-posix.c:189)
Jul 25 12:16:49 ubuntu transmission-daemon[26365]: message repeated 2 times: [ [2017-07-25 12:16:49.422] Couldn't create "/home/debian-transmission": Permission denied (file-posix.c:189)]
Jul 25 12:16:49 ubuntu transmission-daemon[26365]: [2017-07-25 12:16:49.422] UDP Failed to set receive buffer: requested 4194304, got 425984 (tr-udp.c:84)
Jul 25 12:16:49 ubuntu transmission-daemon[26365]: [2017-07-25 12:16:49.422] UDP Failed to set send buffer: requested 1048576, got 425984 (tr-udp.c:95)
Jul 25 12:16:49 ubuntu transmission-daemon[26365]: [2017-07-25 12:16:49.422] Couldn't save temporary file "/home/debian-transmission/.config/transmission-daemon/settings.json.tmp.7GNxAD": No such file or directory (variant.c:1280)
Jul 25 12:38:04 ubuntu transmission-daemon[26365]: Closing transmission session... done.
Jul 25 12:38:10 ubuntu transmission-daemon[26698]: [2017-07-25 12:38:10.154] UDP Failed to set receive buffer: requested 4194304, got 425984 (tr-udp.c:84)
Jul 25 12:38:10 ubuntu transmission-daemon[26698]: [2017-07-25 12:38:10.154] UDP Failed to set send buffer: requested 1048576, got 425984 (tr-udp.c:95)
Jul 25 12:38:48 ubuntu transmission-daemon[26698]: Closing transmission session... done.
Somehow, the system looking for /home/debian-transmission/.config/transmission-daemon/settings.json, but my file is located: /etc/transmission-daemon/settings.json
I am not sure how this happened, looks like it is transmission bug, but I fixed it:
service transmission-daemon stop
mkdir -p /home/debian-transmission/.config/transmission-daemon
chown debian-transmission:debian-transmission /home/debian-transmission/.config/transmission-daemon
cp /etc/transmission-daemon/settings.json /home/debian-transmission/.config/transmission-daemon/settings.json
service transmission-daemon start
