Subject: Re: Router Alert IPv4 Option
To: Darren Reed <>
From: Paul Goyette <>
List: tech-net
Date: 07/22/2001 10:46:00
Well, setscokopt would be a good way to have programs set the option.

But what would you do if you received a packet with the option set?
What would you do differently from receiving the same packet without the

Generally, this option is for routers to have packets delivered to some
process for inspection and processing, even if the packet might not be
addressed to the router itself.  Particularly, it's good to use for a
router where hardware might otherwise just forward packets that the
software should get a chance to handle.  (Like, for example, a IGMP
packet addressed to a group of which the router is not a member but
needs to join!)

On Mon, 23 Jul 2001, Darren Reed wrote:

> In some email I received from, sie wrote:
> > >Has anyone looked at implementing RFC 2113 for NetBSD ?
> > 
> > 	the difficult question is, with what kind of API?
> hmmm, maybe this is exposing my ignorance about it :)  nearly all the
> Ipv4 options are manipulated in one way or another vis setsockopt &
> getsockopt.  What's required?
> Darren

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