Inside our lxd containers, 2147483647 is too large a gid. That setting
will silently fail to be applied (because of the "-" prefix in the
config).

We can apply a smaller range inside containers, like 0-65534, but that
just means that our default will not work, and if you launch a plucky
container you will not have a working ping.

Smaller ranges work, and in fact, since the default ubuntu user is part
of the adm group, gid 4 is the minimum we need (below, "p" is a plucky
lxd container on a noble host):

ubuntu@p:~$ sudo getcap /usr/bin/ping
ubuntu@p:~$ 

ubuntu@p:~$ id
uid=1000(ubuntu) gid=1000(ubuntu) 
groups=1000(ubuntu),4(adm),24(cdrom),27(sudo),30(dip),104(lxd)

ubuntu@p:~$ sudo sysctl net.ipv4.ping_group_range="0 3"
net.ipv4.ping_group_range = 0 3

ubuntu@p:~$ ping 1
ping: socktype: SOCK_RAW
ping: socket: Operation not permitted
ping: => missing cap_net_raw+p capability or setuid?

ubuntu@p:~$ sudo sysctl net.ipv4.ping_group_range="0 4"
net.ipv4.ping_group_range = 0 4

ubuntu@p:~$ ping 1
PING 1 (0.0.0.1) 56(84) bytes of data.

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https://bugs.launchpad.net/bugs/2089938

Title:
  iputils 3:20240905-1 doesn't work for unprivileged users

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