Ssh packet_write_wait: Connection to <host> port: Broken pipe

For some reason when I use OpenSSH_7.9p1, OpenSSL 1.1.1d 10 Sep 2019 I can’t ssh into any hosts. I always get ssh packet_write_wait: Connection to <host> port: Broken pipe. However, if I downgrade my version of ssh with nix-env -f -iA openssh it works.

I’m hoping someone has an idea of how to start debugging this.

I opened a ticket about this a year ago, but I think it got drowned out by other issues at the time. issue 61632

My fix at the time was to override the openssh version in my configuration.nix.

  nixpkgs.config = {
    packageOverrides = pkgs: {
      openssh = (import tarball-1809 {}).openssh;

However, this means I need to build a number of packages myself, including Firefox, which means upgrades take around 8 hours to build. I’ve dealt with this by simply not upgrading as often or at all, but that is not a real solution.

Are these hosts in vmware? There was a bug there that could be worked around by using ssh -o IPQoS=throughput

Yes this host is running in vmware and yes that works perfectly. Thank you so much, this has been a real pain to deal with. I foolishly kept thinking this was a Nixos issue since it happened after an upgrade. I’ll update the issue on github for anyone else that makes the same mistake.


There’s a lot of times when I’m surprised any software works.