DNS doesn't work in v0.4.4

[cdrcnm]

Hello.

After upgrading to greywall v0.3.6 and greyproxy v0.4.4, the DNS requests doesn't work inside the sandbox. Reverting to greyproxy v0.4.3 fix the issue. The TCP requests works fine.

Listening on all interfaces with --host 0.0.0.0 does not fix the issue.

Informations about the issue:

➜ greywall -- sh
$ ss -ulnp; ss -tlnp
State           Recv-Q          Send-Q                   Local Address:Port                     Peer Address:Port          Process
UNCONN          0               0                              0.0.0.0:53                            0.0.0.0:*
State           Recv-Q          Send-Q                   Local Address:Port                     Peer Address:Port          Process
LISTEN          0               5                            127.0.0.1:18321                         0.0.0.0:*
$ cat /etc/resolv.conf
nameserver 127.0.0.1
$ dig  api.anthropic.com
;; communications error to 127.0.0.1#53: timed out
;; communications error to 127.0.0.1#53: timed out
;; communications error to 127.0.0.1#53: timed out

; <<>> DiG 9.18.39-0ubuntu0.24.04.5-Ubuntu <<>> api.anthropic.com
;; global options: +cmd
;; no servers could be reached

On the host:

➜ ss -tulnp | grep 4305
udp   UNCONN 0      0                        127.0.0.1:43053      0.0.0.0:*    users:(("greyproxy",pid=62302,fd=7))
tcp   LISTEN 0      4096                     127.0.0.1:43051      0.0.0.0:*    users:(("greyproxy",pid=62302,fd=3))
tcp   LISTEN 0      4096                     127.0.0.1:43052      0.0.0.0:*    users:(("greyproxy",pid=62302,fd=6))
tcp   LISTEN 0      4096                     127.0.0.1:43053      0.0.0.0:*    users:(("greyproxy",pid=62302,fd=8))

System infos:

Ubuntu 24.04.4 LTS with systemd-resolved

greywall - lightweight, container-free sandbox for running untrusted commands
  Version: 0.3.6
  Built:   2026-05-22T23:56:35Z
  Commit:  1ab2de35d61c7bb9ef49aa3230b32efdde05215e
Platform: linux (kernel 6.17)

Checking system capabilities:
  ✓ bubblewrap
  ✓ socat
  ✓ seccomp
  ✓ landlock (v7)
  ✓ D-Bus isolated (notify-send proxied via xdg-dbus-proxy)
  ✓ xdg-dbus-proxy
  ✓ secret-tool (keyring credential injection for gh/glab)
  ✓ network isolation

greyproxy 0.4.4 (go1.25.10 linux/amd64)
  built:  2026-05-21T15:18:00Z
  commit: f7964ec2c502cd0781700db87b57bec5d8fff1cc