# Two Talks at FOSDEM 2023

> Markdown version of https://dtrautwein.eu/blog/fosdem-2023/

Published 5 February 2023. Tags: talks, ipfs, libp2p.

On 5 February 2023 I gave two 30 minute talks in the Network devroom at [FOSDEM](https://archive.fosdem.org/2023/schedule/speaker/dennis_trautwein/) in Brussels.

## Hole punching in the wild

In the morning I spoke with [Max Leonard Inden](https://archive.fosdem.org/2023/schedule/speaker/max_leonard_inden) about [hole punching in libp2p](https://archive.fosdem.org/2023/schedule/event/network_hole_punching_in_the_wild/). Hole punching lets two peers connect through NATs and firewalls without a central server. We showed how it works and what we learned from running it on IPFS. We showed data from a measurement campaign with volunteers who ran vantage points in their home networks all around the globe. It covers success rates for UDP and TCP, IPv4 and IPv6, how friendly internet providers are to peer-to-peer traffic, and symmetric NATs. This was the data I later used for the IMC '26 paper, [Large-Scale Measurement of NAT Traversal for the Decentralized Web: A Case Study of DCUtR in IPFS](https://dl.acm.org/doi/10.1145/3777912.3809138).

The [slides](https://archive.fosdem.org/2023/schedule/event/network_hole_punching_in_the_wild/attachments/slides/5874/export/events/attachments/network_hole_punching_in_the_wild/slides/5874/2023_fosdem_nat_hole_punching.pdf) and the [recording](https://video.fosdem.org/2023/H.1301%20(Cornil)/network_hole_punching_in_the_wild.mp4) are on the FOSDEM site.

## Decentralized Storage with IPFS

In the afternoon I gave [a talk on my own](https://archive.fosdem.org/2023/schedule/event/network_decentralized_storage/): "Decentralized Storage with IPFS: How Does It Work Under the Hood?". It asks three questions. Who stores my data when I upload it to IPFS? How do I get content back when I only know its hash? How fast is that? I first explain content addressing and content routing.

It is a newer version of the talk I gave at code.talks in Hamburg, see [IPFS Under the Hood, code.talks 2022](/blog/code-talks-ipfs-under-the-hood/). The measurements behind it are in our SIGCOMM '22 paper, [Design and Evaluation of IPFS](https://doi.org/10.1145/3544216.3544232).

The [slides](https://archive.fosdem.org/2023/schedule/event/network_decentralized_storage/attachments/slides/5988/export/events/attachments/network_decentralized_storage/slides/5988/Slides) and the [recording](https://video.fosdem.org/2023/H.1301%20(Cornil)/network_decentralized_storage.mp4) are on the FOSDEM site.