From owner-freebsd-net  Mon Oct 15  9:36:58 2001
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From: Bill Fenner <fenner@research.att.com>
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To: deepika_77@yahoo.com
Subject: Re: mrouted 3.8(how to find multicast members??)
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Date: Mon, 15 Oct 2001 09:36:52 -0700
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> But the definition of threshhold TTL says that a
>incoming multicast packets will be forwarded out of an
>interface only if it has the TTL value >= threshold
>TTL of that interface. Am I right?

No.  Zero is special, and means do not forward.  If you have
the kernel source, check out the ip_mdq() function in
/sys/netinet/ip_mroute.c; the check is:

        if ((rt->mfc_ttls[vifi] > 0) &&
            (ip->ip_ttl > rt->mfc_ttls[vifi])) {

(the threshold > 0 and the TTL > the threshold -- note, >, not >=.)

  Bill

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