Please do as i do in your vps and then maybe the issue reproduced,replace the variable $vps_ip with your real vps ip during the below steps.
wget https://saimei.ftp.acc.umu.se/debian-cd/current/amd64/iso-cd/debian-10.4.0-amd64-netinst.iso
transmission-create -o debian.torrent debian-10.4.0-amd64-netinst.iso
Create a trackerless torrent ,show info on it:
transmission-show debian.torrent
Name: debian-10.4.0-amd64-netinst.iso
File: debian.torrent
GENERAL
Name: debian-10.4.0-amd64-netinst.iso
Hash: a7fbe3ac2451fc6f29562ff034fe099c998d945e
Created by: Transmission/2.92 (14714)
Created on: Mon Jun 8 00:04:33 2020
Piece Count: 2688
Piece Size: 128.0 KiB
Total Size: 352.3 MB
Privacy: Public torrent
TRACKERS
FILES
debian-10.4.0-amd64-netinst.iso (352.3 MB)
Open the port which transmission running on your vps.
firewall-cmd --zone=public --add-port=51413/tcp --permanent
firewall-cmd --reload
Check it from your local pc.
sudo nmap $vps_ip -p51413
Host is up (0.24s latency).
PORT STATE SERVICE
51413/tcp open unknown
Nmap done: 1 IP address (1 host up) scanned in 1.74 seconds
Add the torrent and seed it with transmission's default username and password on your vps(with your own if you already change it):
transmission-remote -n "transmission:transmission" --add debian.torrent
localhost:9091/transmission/rpc/ responded: "success"
transmission-remote -n "transmission:transmission" --list
ID Done Have ETA Up Down Ratio Status Name
1 0% None Unknown 0.0 0.0 None Idle debian-10.4.0-amd64-netinst.iso
Sum: None 0.0 0.0
transmission-remote -n "transmission:transmission" -t 1 --start
localhost:9091/transmission/rpc/ responded: "success"
Get the debian.torrent from your vps into local pc.
scp root@$vps_ip:/root/debian.torrent /tmp
Now to try download it in your local pc.
aria2c --enable-dht=true /tmp/debian.torrent
06/08 09:28:04 [NOTICE] Downloading 1 item(s)
06/08 09:28:04 [NOTICE] IPv4 DHT: listening on UDP port 6921
06/08 09:28:04 [NOTICE] IPv4 BitTorrent: listening on TCP port 6956
06/08 09:28:04 [NOTICE] IPv6 BitTorrent: listening on TCP port 6956
*** Download Progress Summary as of Mon Jun 8 09:29:04 2020 ***
===============================================================================
[#a34431 0B/336MiB(0%) CN:0 SD:0 DL:0B]
FILE: /tmp/debian-10.4.0-amd64-netinst.iso
-------------------------------------------------------------------------------
I wait about one hour ,the download progress is always 0%.
If you're using DHT, you have to open a UDP port in your firewall and then, depending on what you're doing, you can specify that port to aria2c. From the docs:
DHT uses UDP. Since aria2 doesn't configure firewalls or routers for port forwarding, it's up to you to do it manually.
$ aria2c --enable-dht --dht-listen-port=6881 file.torrent
See this page for some more examples of using DHT with aria2c.