wg-multicast - Re: junos filtering msdp "reflector" originator
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- From: Chuck Anderson <>
- To:
- Subject: Re: junos filtering msdp "reflector" originator
- Date: Wed, 11 Mar 2015 10:51:02 -0400
Has anyone tried contacting them?
% Abuse contact for '194.82.152.0 - 194.82.154.255' is
''
inetnum: 194.82.152.0 - 194.82.154.255
netname: CXWEST-3
descr: Imperial College of Science, Technology and Medicine
descr: Core network infrastructure
descr: Was CXWMS which became part of Imperial College in 1997
country: GB
admin-c: ICH1-RIPE
tech-c: ICH1-RIPE
remarks: trouble: Please contact
for abuse problems
status: ASSIGNED PA
mnt-by: JANET-HOSTMASTER
source: RIPE # Filtered
On Wed, Mar 11, 2015 at 04:35:13PM +0200, Zenon Mousmoulas wrote:
> Yes, that router appears to be originating SAs while it is practically
> certain that it is not the RP or the DR for the particular S,Gs and it has
> just discovered them via MSDP. So it appears to be reflecting a large
> portion of the SAs it is originating (which added up to 590 the last time I
> checked). I can't think of any case where such a behavior would make sense;
> it rather seems like misconfiguration or a bug. What do you think?
>
> 10 Μαρ 2015, 17:03, ο/η "Leonard Giuliano"
> <>
> έγραψε:
>
> >
> > Hmm, what do you mean by "reflector"? A router should only originate an
> > SA if it is the local RP and receives a PIM register for the source (or
> > the source is directly connected and the router is the RP and DR on that
> > interface). If the router is not the local RP, it should not originate
> > the SAs. From RFC 3618:
> >
> > 6. Intermediate MSDP Peers
> >
> > Intermediate MSDP speakers do not originate periodic SA messages on
> > behalf of sources in other domains. In general, an RP MUST only
> > originate an SA for a source which would register to it, and ONLY RPs
> > may originate SA messages. Intermediate MSDP speakers MAY forward SA
> > messages received from other domains.
> >
> >
> > On Tue, 10 Mar 2015, Zenon Mousmoulas wrote:
> >
> > | Hi Leonard,
> > |
> > | thanks, yes I figured out that a) I can't filter based on originator
> > (not that it would make much sense in general) and b) peer-rpf check does
> > not consider SA source. They are accepted, perhaps even before rule 4,
> > because the peer is indeed the next hop to the originator. So, to catch
> > such cases, one would need to write MSDP import policies that would
> > reject SAs for sources within one's own address space, which in general
> > should not appear outside one's own PIM domain.
> > |
> > | What I didn't understand however is why that MSDP originator would act
> > as a "reflector", i.e. if there would be any legitimate explanation for
> > such a behavior.
> > |
> > | Thanks for your insight,
> > | Z.
> > |
> > | 9 Μαρ 2015, 23:33, ο/η "Leonard Giuliano"
> > <>
> > έγραψε:
> > |
> > | > Zenon,
> > | >
> > | > You can filter SAs based on source, group or peer, but not originator.
> > | >
> > | > As to the question of whether they should pass peer-rpf, do a "show
> > route
> > | > detail" on the peer (62.40.124.89) as well as the originator
> > | > (194.82.152.254). The results can then be compared against the rpf
> > rules
> > | > in sect 10.1.3 in RFC 3618. You'll probably see it accepted bc of
> > rule
> > | > iv: 62.40.124.89 resides in the AS path in the best path for
> > | > 194.82.152.254.
> > | >
> > | > MSDP peer-rpf doesn't care about the source; rather, it only cares
> > about
> > | > the peer with respect to the originator. Put another way, MSDP will
> > NOT
> > | > decide if it's OK for 194.82.152.254 to originate an SA with source
> > | > 233.21.32.32; it WILL decide if 62.40.124.89 is the peer who should
> > be
> > | > allowed to advertise SAs with the originator of 194.82.152.254.
> > | >
> > | >
> > | > Hope this helps,
> > | > Lenny
> > | >
> > | > On Sat, 28 Feb 2015, Zenon Mousmoulas wrote:
> > | >
> > | > | While investigating an issue with PIM register messages being
> > dropped by
> > | > | our RP routers (due to misconfiguration), I noticed that some S,G
> > state
> > | > | for local sources was mysteriously still present on the RP, even
> > though
> > | > | register messages were being dropped. I then realized this state
> > was
> > | > | triggered by MSDP SAs such as the following, which seem to be
> > originated
> > | > | by some system in the UK. I can't think of a valid scenario where
> > it
> > | > | could be an originator for what is certainly a foreign (in terms of
> > a
> > | > | PIM domain) S,G. Such SAs are being accepted by the router -- I'm
> > not
> > | > | sure at this stage if they should pass peer-rpf-check or not.
> > | > |
> > | > | Group address Source address Peer address Originator
> > Flags
> > | > | 233.21.32.32 62.217.124.105 62.40.124.89 194.82.152.254
> > Accept
> > | > | 233.21.32.234 62.217.124.105 62.40.124.89 194.82.152.254
> > Accept
> > | > |
> > | > | Given these oddities about 194.82.152.254, which seems to act as a
> > MSDP
> > | > | reflector (currently for up to 590 SAs), I wanted to see if I could
> > drop
> > | > | such SAs in the MSDP import policy statement. However there doesn't
> > seem
> > | > | to be a match condition for originator, at least not on JunOS 13.3.
> > I
> > | > | wonder if there is any other way to do this?
> > | > |
> > | > | Regards,
> > | > | Z.
- Re: junos filtering msdp "reflector" originator, Leonard Giuliano, 03/09/2015
- Re: junos filtering msdp "reflector" originator, Zenon Mousmoulas, 03/10/2015
- Re: junos filtering msdp "reflector" originator, Leonard Giuliano, 03/10/2015
- Re: junos filtering msdp "reflector" originator, Zenon Mousmoulas, 03/11/2015
- Re: junos filtering msdp "reflector" originator, Chuck Anderson, 03/11/2015
- Re: junos filtering msdp "reflector" originator, Zenon Mousmoulas, 03/11/2015
- Re: junos filtering msdp "reflector" originator, Leonard Giuliano, 03/11/2015
- Re: junos filtering msdp "reflector" originator, Zenon Mousmoulas, 03/11/2015
- Re: junos filtering msdp "reflector" originator, Chuck Anderson, 03/11/2015
- Re: junos filtering msdp "reflector" originator, Zenon Mousmoulas, 03/11/2015
- Re: junos filtering msdp "reflector" originator, Leonard Giuliano, 03/11/2015
- Re: junos filtering msdp "reflector" originator, Zenon Mousmoulas, 03/11/2015
- Re: junos filtering msdp "reflector" originator, Chuck Anderson, 03/11/2015
- Re: junos filtering msdp "reflector" originator, Zenon Mousmoulas, 03/11/2015
- Re: junos filtering msdp "reflector" originator, Chuck Anderson, 03/11/2015
- Re: junos filtering msdp "reflector" originator, Zenon Mousmoulas, 03/11/2015
- Re: junos filtering msdp "reflector" originator, Leonard Giuliano, 03/10/2015
- Re: junos filtering msdp "reflector" originator, Zenon Mousmoulas, 03/10/2015
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