I don’t understand the file /proc/sys/net/ipv4/conf/default/forwarding. seems I don’t understand either either why veth devices need to read default forwarding value from that and not from kernel sysctl settings. If I have used qemu virtual machines on the same host I have used to “echo 1 > /proc/sys/net/ipv4/ip_forward” but I used to write it only when I need to use qemu virtual machines .
I couldn’t yet find what is setting /proc/sys/net/ipv4/conf/default/forwarding on my host. (it’s set on every time I boot the host)
The topic is still about new containers when they launch, but do you know is the host /proc/sys/net/ipv4/conf/default/forwarding setting a kernel issue or something else? I’m not too expert here but would expect lxc, libvirt and other projects to set the /proc/sys/net/ipv4/ip_forward only
grep forw /etc/sysctl.d/*
/etc/sysctl.d/99-sysctl.conf:# Uncomment the next line to enable packet forwarding for IPv4
/etc/sysctl.d/99-sysctl.conf:#net.ipv4.ip_forward=1
/etc/sysctl.d/99-sysctl.conf:# Uncomment the next line to enable packet forwarding for IPv6
/etc/sysctl.d/99-sysctl.conf:#net.ipv6.conf.all.forwarding=1
grep forw /etc/sysctl.conf
# Uncomment the next line to enable packet forwarding for IPv4
#net.ipv4.ip_forward=1
# Uncomment the next line to enable packet forwarding for IPv6
#net.ipv6.conf.all.forwarding=1
Thanks