What is the correct way to enable IP-forwarding in MacOS X?

More specifically, what is the MacOS X command line quivalent of the following two Linux commands:

echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -A FORWARD -j ACCEPT

1 Answer 1


You're doing two things there.

  1. Enabling IP forwarding. The OS X equivalent might be:

    sysctl -w net.inet.ip.forwarding=1

    ...but since I don't know exactly what you're trying to do, this might be technically correct but unhelpful.

  2. Adding a largely unnecessary firewall rule. If you haven't changed the default policy for your FORWARD chain (iptables -P FORWARD ...), then this rule does nothing.

    OS X uses the pf firewall tools. Try here

    Prior to 10.7 Lion, OS X used the ipfw firewall tools, which are well documented all over the net. Try here, or here

  • This is exactly what I needed to enable a proper switch on my Bridge virtual interface. Catalina.
    – Ray Foss
    Jun 23, 2020 at 19:37

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