rootless containers cannot ping hosts

[netsho]

Hello,

I'm unable to ping another host from rootless container.
Context : I'm running Homepage container, behind nginx proxy container, using the same created network (bridge network). No problem for communications between containers.
From Homepage, I'm trying to ping a server on my LAN, to enable the uptime check of the server. It didn't work.
I used the CLI command to ensure the ping is not working podman exec homepage ping -c 4 192.168.1.36.
Output :

PING 192.168.1.36 (192.168.1.36): 56 data bytes

--- 192.168.1.36 ping statistics ---
4 packets transmitted, 0 packets received, 100% packet loss

On the troubleshooting documentation, I came by the same problem : 5) rootless containers cannot ping
I used the command # sysctl -w "net.ipv4.ping_group_range=0 2000000", and also persisting this change by adding it to the /etc/sysctl.conf file : net.ipv4.ping_group_range=0 2147483647

Tried both the ranges. I found this range 0 2147483647 in #2488.

Applied the modifications and restarted the Homepage container. I still cannot ping the ip address.

Do you have any idea how to resolve this issue ?

Thank you in advance for your help.

[sbrivio-rh]

What versions of things are you using?

[netsho]

Podman's version podman version 4.9.3

Podman info:

host:
  arch: amd64
  buildahVersion: 1.33.7
  cgroupControllers:
  - cpu
  - memory
  - pids
  cgroupManager: systemd
  cgroupVersion: v2
  conmon:
    package: conmon_2.1.10+ds1-1build2_amd64
    path: /usr/bin/conmon
    version: 'conmon version 2.1.10, commit: unknown'
  cpuUtilization:
    idlePercent: 95.71
    systemPercent: 0.95
    userPercent: 3.34
  cpus: 2
  databaseBackend: sqlite
  distribution:
    codename: noble
    distribution: ubuntu
    version: "24.04"
  eventLogger: journald
  freeLocks: 2006
  hostname: homelab-services
  idMappings:
    gidmap:
    - container_id: 0
      host_id: 1000
      size: 1
    - container_id: 1
      host_id: 100000
      size: 65536
    uidmap:
    - container_id: 0
      host_id: 1000
      size: 1
    - container_id: 1
      host_id: 100000
      size: 65536
  kernel: 6.8.0-52-generic
  linkmode: dynamic
  logDriver: journald
  memFree: 959344640
  memTotal: 8290947072
  networkBackend: netavark
  networkBackendInfo:
    backend: netavark
    dns:
      package: aardvark-dns_1.4.0-5_amd64
      path: /usr/lib/podman/aardvark-dns
      version: aardvark-dns 1.4.0
    package: netavark_1.4.0-4_amd64
    path: /usr/lib/podman/netavark
    version: netavark 1.4.0
  ociRuntime:
    name: crun
    package: crun_1.14.1-1_amd64
    path: /usr/bin/crun
    version: |-
      crun version 1.14.1
      commit: de537a7965bfbe9992e2cfae0baeb56a08128171
      rundir: /run/user/1000/crun
      spec: 1.0.0
      +SYSTEMD +SELINUX +APPARMOR +CAP +SECCOMP +EBPF +WASM:wasmedge +YAJL
  os: linux
  pasta:
    executable: /usr/bin/pasta
    package: passt_0.0~git20240220.1e6f92b-1_amd64
    version: |
      pasta unknown version
      Copyright Red Hat
      GNU General Public License, version 2 or later
        <https://www.gnu.org/licenses/old-licenses/gpl-2.0.html>
      This is free software: you are free to change and redistribute it.
      There is NO WARRANTY, to the extent permitted by law.
  remoteSocket:
    exists: true
    path: /run/user/1000/podman/podman.sock
  security:
    apparmorEnabled: false
    capabilities: CAP_CHOWN,CAP_DAC_OVERRIDE,CAP_FOWNER,CAP_FSETID,CAP_KILL,CAP_NET_BIND_SERVICE,CAP_SETFCAP,CAP_SETGID,CAP_SETPCAP,CAP_SETUID,CAP_SYS_CHROOT
    rootless: true
    seccompEnabled: true
    seccompProfilePath: /usr/share/containers/seccomp.json
    selinuxEnabled: false
  serviceIsRemote: false
  slirp4netns:
    executable: /usr/bin/slirp4netns
    package: slirp4netns_1.2.1-1build2_amd64
    version: |-
      slirp4netns version 1.2.1
      commit: 09e31e92fa3d2a1d3ca261adaeb012c8d75a8194
      libslirp: 4.7.0
      SLIRP_CONFIG_VERSION_MAX: 4
      libseccomp: 2.5.5
  swapFree: 4050120704
  swapTotal: 4066373632
  uptime: 14h 24m 48.00s (Approximately 0.58 days)
  variant: ""
plugins:
  authorization: null
  log:
  - k8s-file
  - none
  - passthrough
  - journald
  network:
  - bridge
  - macvlan
  - ipvlan
  volume:
  - local
registries: {}
store:
  configFile: /home/netsho/.config/containers/storage.conf
  containerStore:
    number: 16
    paused: 0
    running: 16
    stopped: 0
  graphDriverName: overlay
  graphOptions: {}
  graphRoot: /home/netsho/.local/share/containers/storage
  graphRootAllocated: 155108065280
  graphRootUsed: 22262059008
  graphStatus:
    Backing Filesystem: extfs
    Native Overlay Diff: "true"
    Supports d_type: "true"
    Supports shifting: "false"
    Supports volatile: "true"
    Using metacopy: "false"
  imageCopyTmpDir: /var/tmp
  imageStore:
    number: 18
  runRoot: /tmp/containers-user-1000/containers
  transientStore: false
  volumePath: /home/netsho/.local/share/containers/storage/volumes
version:
  APIVersion: 4.9.3
  Built: 0
  BuiltTime: Thu Jan  1 00:00:00 1970
  GitCommit: ""
  GoVersion: go1.22.2
  Os: linux
  OsArch: linux/amd64
  Version: 4.9.3

Podman networks:

NETWORK ID    NAME                 DRIVER
0153cc708ca1  nginx-proxy-network  bridge
2f259bab93aa  podman               bridge

Inspect custom network, ie nginx-proxy-network used in all containers:

[
     {
          "name": "nginx-proxy-network",
          "id": "0153cc708ca1613aa90dfccad3229e35dc72b4cb40fd370a320f7ecb0f44192d",
          "driver": "bridge",
          "network_interface": "podman1",
          "created": "2024-12-15T14:58:21.744471619Z",
          "subnets": [
               {
                    "subnet": "10.89.0.0/24",
                    "gateway": "10.89.0.1"
               }
          ],
          "ipv6_enabled": false,
          "internal": false,
          "dns_enabled": true,
          "ipam_options": {
               "driver": "host-local"
          }
     }
]

Network settings of Homepage container (inspect command):

"NetworkSettings": {
               "EndpointID": "",
               "Gateway": "",
               "IPAddress": "",
               "IPPrefixLen": 0,
               "IPv6Gateway": "",
               "GlobalIPv6Address": "",
               "GlobalIPv6PrefixLen": 0,
               "MacAddress": "",
               "Bridge": "",
               "SandboxID": "",
               "HairpinMode": false,
               "LinkLocalIPv6Address": "",
               "LinkLocalIPv6PrefixLen": 0,
               "Ports": {
                    "3000/tcp": null
               },
               "SandboxKey": "/run/user/1000/netns/netns-9f0e7ce2-a976-96c6-8f6e-f9e794c69359",
               "Networks": {
                    "nginx-proxy-network": {
                         "EndpointID": "",
                         "Gateway": "10.89.0.1",
                         "IPAddress": "10.89.0.4",
                         "IPPrefixLen": 24,
                         "IPv6Gateway": "",
                         "GlobalIPv6Address": "",
                         "GlobalIPv6PrefixLen": 0,
                         "MacAddress": "de:9e:7b:15:70:f7",
                         "NetworkID": "nginx-proxy-network",
                         "DriverOpts": null,
                         "IPAMConfig": null,
                         "Links": null,
                         "Aliases": [
                              "homepage",
                              "9625fe091d42"
                         ]
                    }
               }
          },

The Homepage container doesn't export port because i have reverse proxy behind.

[sbrivio-rh]

Podman's version podman version 4.9.3

I think you're using the wrong version of Debian for your purposes. Debian stable makes sense if you have a production environment that needs to run critical systems without interruptions, but then I wouldn't expect that you experiment with containers this way. You should probably be using Debian testing, see also https://www.debian.org/doc/manuals/debian-faq/choosing.en.html#s3.1.3.

Here, at least personally, I only help out with the latest versions. See also #24633 (reply in thread), #25219, etc.

[netsho]

I came by your comment in #25219:

But should we really encourage users to come up with "solutions" that will cause them continued troubles and everybody else unnecessary maintenance burden (see #25269 among dozens of examples) because they fundamentally misunderstand how Debian and Ubuntu versions work?

I speak as a Debian maintainer rather than as a Red Hat developer here.

You were right. I never came by (or tried to search) how Ubuntu versions work. When i want to install ubuntu desktop/server, I blindly choose the LTS version, because... the long term support is appealing.
Anyway, thank you very much for the clarification. I'll go with your solution, switching to Debian testing as it makes more sense for my purpose.

Have a good day.

[netsho]

Just to give a heads up, the solution 5) rootless containers cannot ping in the troubleshooting documentation worked after upgrading the Ubuntu version to 24.10, which means upgrading podman too.

Thank you for your help @sbrivio-rh.

[sbrivio-rh]

I'm glad it helped, thanks for re-testing!