Always a bunch of them out there. Sometimes accidental, sometimes from
folks who are trying to do something , just using ineffective methods to do
it.
On Tue, Oct 18, 2022 at 10:21 Sandoiu Mihai wrote:
> Hi
>
>
>
> We have witnessed a lot of prepending in the last days, we got a
On Tue, Oct 18, 2022 at 4:59 AM Sandoiu Mihai wrote:
> We have witnessed a lot of prepending in the last days, we got a few internet
> routes that have 30…200 prepends, did you face the same issue?
Hi Sandoiu,
Not a direct answer to your question, but broadly speaking any route
with an A
Sandoiu Mihai wrote on 18/10/2022 12:59:
We have witnessed a lot of prepending in the last days, we got a few
internet routes that have 30…200 prepends, did you face the same issue?
Not sure that this is causing an operational problem? If you don't like
it, then nothing is stopping you
Hi
We have witnessed a lot of prepending in the last days, we got a few internet
routes that have 30...200 prepends, did you face the same issue?
Regards
Mihai
> -Original Message-
> From: NANOG On
> Behalf Of Joe Maimon
> Sent: Thursday, March 31, 2022 6:20 PM
> Subject: Re: DMARC ViolationAS21299 - 46.42.196.0/24 ASN prepending 255
> times
>
> [...]
> I think more and perhaps different knobs were and still are needed
Matthew Petach wrote:
Unfortunately, the reason crazy-long prepends actually propagate so
widely in the internet core is because most of those decisions to prefer
your peer's customers are done using a relatively big and heavy hammer.
IOW if your peer or customer has prepended 5 times or
t practice
> procedures?
> >
> > That said, prepending pretty much anything more than your current view
> > of the Internet's diameter in ASNs is useless in practice. Cascading
> > effects are considered in
> > https://datatracker.ietf.org/doc/draft-ietf-grow
Joe Provo wrote:
On Fri, Mar 25, 2022 at 11:08:01AM +0300, Paschal Masha wrote:
:) probably the longest prepend in the world.
A thought though, is it breaking any standard or best practice procedures?
That said, prepending pretty much anything more than your current view
of the Internet&#
-length distribution in my RIB as of a few minutes ago.
Like everyone else, I do some moderately strange things for including
artificially locally prepending routes from some of my upstreams, so I’m quite
certain no-one else’s will exactly match mine. The overall shape of the
distribution, though
On Sun, 27 Mar 2022 at 18:31, Jon Lewis wrote:
> Is prepending used for any purpose other than TE? The point I think Joe
> was trying to make was prepending once or even a few times has uses.
> Prepending more than a few times is unlikely to accomplish anything a few
> prepends did
On Fri, 25 Mar 2022, Baldur Norddahl wrote:
On Fri, 25 Mar 2022 at 17:32, Joe Provo wrote:
That said, prepending pretty much anything more than your current view
of the Internet's diameter in ASNs is useless in practice.
That is one way of viewing it. But prepending can al
ompson*
> Consultant, Infrastructure Services
> [image: MERLIN]
> 100 - 135 Innovation Drive
> Winnipeg, MB, R3T 6A8
> (204) 977-6824 or 1-800-430-6404 (MB only)
> athomp...@merlin.mb.ca
> www.merlin.mb.ca
>
>
>
> *From:* NANOG *On Behalf
> Of *Tom Beecher
> *Se
On Fri, Mar 25, 2022 at 6:19 PM Amir Herzberg wrote:
> Hi Matthew and NANOG,
>
> I don't want to defend prepending 255 times, and can understand filtering
> of extra-prepended-announcements, but I think Matthew may not be correct
> here:
>
>> Anyone that is prepend
Hi Matthew and NANOG,
I don't want to defend prepending 255 times, and can understand filtering
of extra-prepended-announcements, but I think Matthew may not be correct
here:
> Anyone that is prepending to do traffic engineering is
> doing *differential* prepending; that is, a longer
ds as a way
to signal "infinite" distance--essentially, "unreachable"
for that prefix along that path.
Anyone that is prepending to do traffic engineering is
doing *differential* prepending; that is, a longer number
of prepends along one path, with a shorter set of prepend
Ask your upstream providers for a BGP community tag that lowers localpref below
100 within their network. Set that community tag on any backup routes along
with your (moderate) path prepending.
The backup upstream will then install that route only if there is no other way
to get to your AS
omp...@merlin.mb.ca>
www.merlin.mb.ca<http://www.merlin.mb.ca/>
From: NANOG On Behalf Of Tom
Beecher
Sent: Friday, March 25, 2022 4:13 PM
To: Paschal Masha
Cc: nanog
Subject: Re: DMARC ViolationAS21299 - 46.42.196.0/24 ASN prepending 255 times
The best practice with regards to as_path lengt
Message -
> From: "Erik Sundberg"
> To: "nanog"
> Sent: Friday, March 25, 2022 6:43:38 AM
> Subject: DMARC ViolationAS21299 - 46.42.196.0/24 ASN prepending 255 times
>
> If anyone from AS21299 is lurking on Nanog. Please reduce your AS prepends
>
On Fri, 25 Mar 2022 at 17:32, Joe Provo wrote:
> That said, prepending pretty much anything more than your current view
> of the Internet's diameter in ASNs is useless in practice.
>
That is one way of viewing it. But prepending can also be used for traffic
engineering. I could p
le to many
and fragile for the rest [see
https://blog.apnic.net/2019/07/15/excessive-bgp-as-path-prepending-is-a-self-inflicted-vulnerability/].
That said, prepending pretty much anything more than your current view
of the Internet's diameter in ASNs is useless in practice. Cascading
effects are c
Paschal Masha writes:
> :) probably the longest prepend in the world.
>
> A thought though, is it breaking any standard or best practice procedures?
Don't think so. But there is this draft suggesting max 5:
https://datatracker.ietf.org/doc/draft-ietf-grow-as-path-prepending/
Bjørn
2 6:43:38 AM
Subject: DMARC ViolationAS21299 - 46.42.196.0/24 ASN prepending 255 times
If anyone from AS21299 is lurking on Nanog. Please reduce your AS prepends for
46.42.196.0/24 from 255 prepends to a more reasonable number of prepends let's
say 20. Thanks!
This is a Kazakhstan
From: sur...@mauigateway.com
Sent: Thursday, March 24, 2022 11:45 PM
To: Erik Sundberg ; nanog@nanog.org
Subject: Re: AS21299 - 46.42.196.0/24 ASN prepending 255 times
On 3/24/2022 5:43 PM, Erik Sundberg wrote:
If anyone from AS21299 is lurking on Nanog. Please reduce your AS
On 3/24/2022 5:43 PM, Erik Sundberg wrote:
If anyone from AS21299 is lurking on Nanog. Please reduce your AS prepends for
46.42.196.0/24 from 255 prepends to a more reasonable number of prepends let's
say 20. Thanks!
This is a Kazakhstan register IP Block and ASN
Network Next Hop Me
If anyone from AS21299 is lurking on Nanog. Please reduce your AS prepends for
46.42.196.0/24 from 255 prepends to a more reasonable number of prepends let's
say 20. Thanks!
This is a Kazakhstan register IP Block and ASN
Network Next Hop Metric LocPrf Weight Path
*> 46.42.196.0/24
>> this is called path poisoning. an italian friend used it in his phd
>> thesis. a few friends and i used it to detect use of default across
>> the internet.
>
> I've done this in the past as a work-around for insufficient BGP
> community support. Just prependi
On Fri, 16 Dec 2016, Randy Bush wrote:
this is called path poisoning. an italian friend used it in his phd
thesis. a few friends and i used it to detect use of default across
the internet.
I've done this in the past as a work-around for insufficient BGP community
support. Just prepe
On 17 Dec 2016, at 0:13, Job Snijders wrote:
There are providers who inspect the AS_PATH's contents and make
decisions to reject (ignore) a route announcement or
not based on the presence of certain values.
+1
---
Roland Dobbins
Hi Andrew,
On Thu, Dec 15, 2016 at 01:54:34PM -0500, Andrew Imeson wrote:
> Is it acceptable to prepend using another networks ASN as long as your
> ASN is the last one in the path? I can think of a few scenarios where
> this is helpful.
Your milage may vary. You risk introducing breakage instead
this is called path poisoning. an italian friend used it in his phd
thesis. a few friends and i used it to detect use of default across
the internet.
but 42 people will scream "that's my AS!" of course, as it is your
prefix, that is ASinine :)
ramdu
Even in that case I believe you should encapsulate between two instances of
your own ASN. Your example follows this but the text says only about the
last one in the path, while having both last and at least one previous is
better since you won't be implying that some other AS has connection to yet
Is it acceptable to prepend using another networks ASN as long as your
ASN is the last one in the path? I can think of a few scenarios where
this is helpful.
One scenario: Anycast content provider with an ISP (who you aren't
directly peering with) is choosing to send all traffic to a PoP on
anothe
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