Hello,

I'm currently trying to find a bug in my system and I'm not sure if this is because of some ROS2 setting. So I'd like to apologize if it turns out not ROS related.

The setup:

• RasperryPi (RPI) with Ubuntu 22.04.2 and ROS2 Humble installation
• Ubuntu host (Base) with Humble Docker container with network=host mode

I followed these instructions to setup the RPI:link text

The connection works perfectly when the RPI is connected via Ethernet:

1. Ping Base or 8.8.8.8 works
2. ros2 multicast send/receive from Base <=> RPI works
3. ros2 demo talker/listener from Base <=> RPI works

As soon as I disconnect the Ethernet cable from the RPI:

1. Ping Base or 8.8.8.8 works
2. ros2 multicast send/receive from Base <=> RPI doesn't work

3. ros2 demo talker/listener from Base <=> RPI doesn't work

   ethernets:
       eth0:
           dhcp4: true
           optional: true
   version: 2
   wifis:
       wlan0:
           dhcp4: true
           optional: true
           access-points:
               "SSID":
                    password: "PW"
   

Output of ip a:

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN group default qlen 1000
    link/ether b8:27:eb:65:49:71 brd ff:ff:ff:ff:ff:ff
3: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether b8:27:eb:30:1c:24 brd ff:ff:ff:ff:ff:ff
    inet 192.168.178.92/24 metric 600 brd 192.168.178.255 scope global dynamic wlan0
       valid_lft 859145sec preferred_lft 859145sec
    inet6 2003:ec:7f28:1800:ba27:ebff:fe30:1c24/64 scope global dynamic mngtmpaddr noprefixroute 
       valid_lft 7014sec preferred_lft 1614sec
    inet6 fe80::ba27:ebff:fe30:1c24/64 scope link 
       valid_lft forever preferred_lft forever

I'm running out of ideas where I should look into or if I made a mistake in the ROS2 setup. Any advice would be highly appreciated.

Thanks!