Running torrent tracker on a local host

am1x · 03-18-2019, 02:12 AM

Hi everyone,
I want to share big files via bitTorrent.
I've set up a tracker opentracker listening to port 6969, and a client kTorrent listening to port 6881. My network uses NAT. I create a torrent file, set the tracker as http://<external_ip>:6969/announce, the client tries to connect to it and shows "Could not connect to host localhost" message. If I use local ip (192.168.1.2) I can connect to the tracker, but other peers see my ip as 192.168.1.2.
If all clients are inside the same LAN they manage to share files this way. Port forwarding works fine, the tracker is reachable from outside.
I don't have a router that supports NAT loopback, but I'm looking for some workaround to do the same thing with software.

nini09 · 03-20-2019, 02:46 PM

You can use iptable to open some port.

am1x · 03-20-2019, 11:16 PM

How to do it? I'm new to it so could you explain me step by step, which commands should I use?
I tried using these iptables rules but it doesn't work, other peers still see my ip as 192.168.1.2.

Code:

iptables -t nat -I OUTPUT -p tcp -m tcp --dport 6969 -d <external_ip>/32 -j DNAT --to-destination 192.168.1.2
iptables -t nat -I OUTPUT -p tcp -m tcp --dport 6881 -d <external_ip>/32 -j DNAT --to-destination 192.168.1.2
iptables -t nat -I POSTROUTING -p tcp -m tcp --sport 6881 -s 192.168.1.2/24 -d 192.168.1.2 -j SNAT --to-source <external_ip>
iptables -t nat -I POSTROUTING -p tcp -m tcp --sport 6969 -s 192.168.1.2/24 -d 192.168.1.2 -j SNAT --to-source <external_ip>

nini09 · 03-21-2019, 03:02 PM

7.4.1. DMZs and iptables
iptables rules can be set to route traffic to certain machines, such as a dedicated HTTP or FTP server, in a demilitarized zone (DMZ) — a special local subnetwork dedicated to providing services on a public carrier such as the Internet. For example, to set a rule for routing incoming HTTP requests to a dedicated HTTP server at 10.0.4.2 (outside of the 192.168.1.0/24 range of the LAN), NAT calls a PREROUTING table to forward the packets to their proper destination:

iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j DNAT \ --to-destination 10.0.4.2:80

With this command, all HTTP connections to port 80 from the outside of the LAN are routed to the HTTP server on a separate network from the rest of the internal network. This form of network segmentation can prove safer than allowing HTTP connections to a machine on the network. If the HTTP server is configured to accept secure connections, then port 443 must be forwarded as well.

am1x · 04-06-2019, 08:15 AM

I don't have a router with iptables. Port forwarding works fine, the tracker is reachable from outside. I can't connect to it from the client running on the same PC.