this post was submitted on 02 Jan 2026
92 points (98.9% liked)
Programming
24348 readers
218 users here now
Welcome to the main community in programming.dev! Feel free to post anything relating to programming here!
Cross posting is strongly encouraged in the instance. If you feel your post or another person's post makes sense in another community cross post into it.
Hope you enjoy the instance!
Rules
Rules
- Follow the programming.dev instance rules
- Keep content related to programming in some way
- If you're posting long videos try to add in some form of tldr for those who don't want to watch videos
Wormhole
Follow the wormhole through a path of communities !webdev@programming.dev
founded 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
We deployed a client software in a Docker container on Windows 10. It could not connect to the backend, even though we saw SYN packages originating from it.
So, we ran WireShark on the Windows host and saw that the SYN-ACK packages from the backend were arriving there, too, but no ACK came through to complete the TCP handshake.
Eventually, we rolled out a network debugging container on that Windows host and then could see in the tcpdump, that the SYN-ACK packages, which arrived on the Windows host, just did not show up in the container. Hyper-V or something was quietly dropping them.
Other network connections were working fine, just the SYN-ACK from our backend triggered this.