kernel-parameters.md

Configure Kernel Parameters

Note Parameters will be automatically configured if global.auto_config_kernel_parameter is true.

If you set up dae as a router or other intermediate device and bind it to LAN interfaces, you need to adjust some Linux kernel parameters to make everything work fine. By default, the latest Linux distributions have IP Forwarding disabled. In the case where we need to up a Linux router/gateway or a VPN server or simply a plain dial-in server, then we need to enable forwarding. Moreover, in order to keep our gateway position and keep correct downstream route table, we should disable send-redirects. Do the followings to adjust Linux kernel parameters:

For every LAN interfaces you want to proxy:

export lan_ifname=docker0

sudo tee /etc/sysctl.d/60-dae-lan-$lan_ifname.conf << EOF
net.ipv4.conf.$lan_ifname.forwarding = 1
net.ipv6.conf.$lan_ifname.forwarding = 1
net.ipv4.conf.$lan_ifname.send_redirects = 0
EOF
sudo sysctl --system

It is also recommended to enable IPv4 and IPv6 forward to avoid weird situations:

echo "net.ipv4.ip_forward = 1" | sudo tee /etc/sysctl.d/60-ip-forward.conf
echo "net.ipv6.conf.all.forwarding = 1" | sudo tee /etc/sysctl.d/60-ip-forward.conf
sudo sysctl --system

Please modify docker0 to your LAN interface.

For your WAN interfaces that accept RA:

export wan_ifname=eth0

if [ "$(cat /proc/sys/net/ipv6/conf/$wan_ifname/accept_ra)" == "1" ]; then
    sudo tee /etc/sysctl.d/60-dae-wan-$wan_ifname.conf << EOF
net.ipv6.conf.$wan_ifname.accept_ra = 2
EOF
    sudo sysctl --system
fi

Please modify eth0 to your WAN interface.

Setting accept_ra to 2 if it is 1 because net.ipv6.conf.all.forwarding = 1 will suppress it. See https://sysctl-explorer.net/net/ipv6/accept_ra/ for more information.