0

I am using Transmission BitTorrent client and Retroshare from behind a NAT firewall with port-forwarding/UPnP disabled. However, I still seem to be able to accept incoming connections with these programs, and I am curious how this is possible. In the case of Transmission, I can see the 'I' flag on some peers, which indicates they are an incoming connection. And in the case of Retroshare, I am able to connect with friends that are also behind a NAT firewall. Does anyone know how this is possible from behind a firewall? Is Transmission (and possibly other P2P clients too) doing some kind of NAT traversal? What kind of NAT traversal might they be using?

DBear
  • 312
  • 2
  • 9
  • Does this answer your question? [How NAT traversal works in case of peer to peer protocols like bittorrent.](https://stackoverflow.com/questions/37367769/how-nat-traversal-works-in-case-of-peer-to-peer-protocols-like-bittorrent) – the8472 Jun 12 '21 at 08:03
  • That does not directly answer my question. Most of the points in the answer either would not work on my network or do not enable incoming connections. However, it mentioned ut_holepunch, and after some searching, I found [this thread](http://forum.transmissionbt.com/viewtopic.php?t=10308), which claims that Transmission does not use ut_holepunch, but it does use Teredo (which I have never heard of until now) to achieve the same goal. So that Q/A you linked did not directly answer my question, but it led me in the right direction to find an answer. – DBear Jun 14 '21 at 12:34
  • *"either would not work on my network"* - well, these are general programming questions, not tailored to your network or application use which you didn't even mention. You should ask on superuser if you want support rather than programming help/general technical understanding. *"do not enable incoming connections"* all but one point are about directly or indirectly facilitating incoming connections – the8472 Jun 14 '21 at 19:20

0 Answers0