Rdesktop on Unraid in container net 3389 not advertising/listening

Running unraid 7.0.0, rdesktop on latest tag release (Alpine XFCE) as of today. I’m running this inside a container network (privoxy), and have found that rdesktop doesn’t appear to be listening on 3389. Works fine outside the container network, but, for this setup it’s required to delete the -p option on the rdesktop container as the container hosting the containerized network handles the container/host port translations. Other containers working fine on the same setup.

I suspected something wrong with the container net at first, but firewall rules, etc, all look right.
Troubleshooting I note when curling localhost on 3389 (from within the rdesktop shell), it reports not listening, cat /proc/net/tcp | grep “:0D3D” also reports similar.

I can’t tell you the latest built of rdesktop this worked on, as I keep it up to date, however I have tried rdesktop ubuntu flavors for testing as well, with the same results. I did note this problem post-7.0.0 unraid upgrade however, which may or may not be a coincidence.

It’s acting as if when the -p option is missing from the compose, that it won’t bind anything to 3389.

Any suggestions?

This is solved.

I’ve identified two potential issues (at least with the :latest tag release) when running inside a VPN container network:

  1. IPv6 Binding Issue:
    xrdp-sesman only binds to IPv6 (:::3350) inside the VPN network, preventing xrdp from connecting via IPv4 (127.0.0.1:3350).
    Manually disabling IPv6 with --sysctl net.ipv6.conf.all.disable_ipv6=1 forces it to bind correctly to IPv4.
  2. Incorrect Desktop Environment:
    The container is XFCE-based (xfce4-session installed) but defaults to launching KDE (startplasma-x11) in /config/startwm.sh.
    Updating startwm.sh to use /usr/bin/startxfce4 resolves that issue.