Re: [PATCH] net:ipv4: Packet is not forwarded if bc_forwarding not configured on ingress interface

From: David Ahern
Date: Sun Feb 28 2021 - 22:21:26 EST


On 2/28/21 5:53 PM, Henry Shen wrote:
> When an IPv4 packet with a destination address of broadcast is received
> on an ingress interface, it will not be forwarded out of the egress
> interface if the ingress interface is not configured with bc_forwarding
> but the egress interface is. If both the ingress and egress interfaces
> are configured with bc_forwarding, the packet can be forwarded
> successfully.
>
> This patch is to be inline with Cisco's implementation that packet can be
> forwarded if ingress interface is NOT configured with bc_forwarding,
> but egress interface is.
>

In Linux, forwarding decisions are made based on the ingress device, not
the egress device.