Subject: Re: Should loose source routing be enabled if not IPFORWARDING?
To: Charles M. Hannum <>
From: John Hawkinson <>
List: current-users
Date: 12/14/1994 02:14:29
> From: "Charles M. Hannum" <>

Quoting me:
>    This is correct behavior, as documented by RFC1122, which states on
>    page 35, under section `` Options: RFC-791 Section 3.2'',
>    subsection (c) Source Route Options:
> 	     A host MUST support originating a source route and MUST be
> 	     able to act as the final destination of a source route.
> This imples by omission that it's legal for a host to not act as an
> intermediary for source routing.

Sigh. Open Mouth, Insert Foot. This is the price I pay for trying
to give the same answer to two slightly different questions.
Indeed, the appropriate section is ``3.3.5  Source Route Forwarding''
which states:

         Subject to restrictions given below, a host MAY be able to act
         as an intermediate hop in a source route, forwarding a source-
         routed datagram to the next specified hop.

Where MAY is formally defined as:

         *    "MAY"

              This word or the adjective "OPTIONAL" means that this item
              is truly optional.  One vendor may choose to include the
              item because a particular marketplace requires it or
              because it enhances the product, for example; another
              vendor may omit the same item.

Nevertheless, my previous comments still apply -- it is legal for a
host to ignore non-local source routing, but NetBSD's current behavior
of permitting it is legal as well (though optional per 1122), and,
IMHO, desirable.

John Hawkinson