lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Thu, 13 Aug 2015 16:52:32 +0000
From:	Philip Downey <>
To:	Andrew Lunn <>
CC:	David Miller <>,
	"" <>,
	"" <>,
	"" <>,
	"" <>,
	"" <>,
	"" <>
Subject: RE: [PATCH] IGMP: Inhibit reports for local multicast groups

Hi Andrew
IGMP snooping is designed to prevent hosts on a local network from receiving traffic for a multicast group they have not explicitly joined.   Link-Local multicast traffic should not have an IGMP client since it is reserved for routing protocols.  One would expect that IGMP snooping needs to ignore local multicast traffic in the reserved range intended for routers since there should be no IGMP client to make "join" requests.



> -----Original Message-----
> From: Andrew Lunn []
> Sent: Thursday, August 13, 2015 5:06 PM
> To: Philip Downey
> Cc: David Miller;;; yoshfuji@...ux-
> Subject: Re: [PATCH] IGMP: Inhibit reports for local multicast groups
> On Thu, Aug 13, 2015 at 02:48:23PM +0000, Philip Downey wrote:
> > Hi David
> > Thanks for taking the time to review and comment.
> > This is my first upstream request so please forgive any ignorance on my
> part.   I have added a new proposed commit wording below with a view to
> agreeing the content before resubmitting the patch.
> > I hope it is sufficient to address your concerns.
> >
> >    IGMP: Inhibit reports for local multicast groups
> >
> >     The range of addresses between and
> >     inclusive, is reserved for the use of routing protocols and other
> >     low-level topology discovery or maintenance protocols, such as
> >     gateway discovery and group membership reporting.  Multicast
> >     routers should not forward any multicast datagram with   destination
> >     addresses in this range, regardless of its TTL.
> >
> >     Currently, IGMP reports are generated for this reserved range of
> >     addresses even though a router will ignore this information since
> >     it has no purpose.
> Hi Philip
> What about switches which are doing IGMP snooping?
>      Andrew
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to
More majordomo info at

Powered by blists - more mailing lists