Cymru Bogon AS path change
Rabbi Rob Thomas
robt at cymru.com
Mon Sep 16 17:34:15 UTC 2013
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Hi again, NANOGers.
> My apologies! We had a configuration "oops" during a migration to a new
> back-end infrastructure. We're working through that now, and I believe
> we have it sorted. I'll send out a more gory detailed update in a bit.
We're moving from Cisco gear to bird routing software
(http://bird.network.cz) and there was a misconfiguration in one of our
route reflectors. We tested this extensively but in a limited
Unfortunately we didn't notice it until we brought all of the changes
Since we've been at this a while, we figured there would be a couple of
interesting "features" that arose during the change. :) We sent out an
announcement of the change window to our bogon peers. Ben, did we miss
you? If so, I apologize and please let me know. We'll ensure you're on
the list for the next update. I probably should have sent this along to
a few lists such as NANOG. Here's the announcement for the benefit of all:
- --- snip snip ---
Dear bogon feed subscriber,
You are receiving this note because you are peering with one or more of
our bogon route servers via BGP. Please be informed that there will be
a maintenance window for the bogon route server project on Monday,
September 16th from 14:00 to 18:00 GMT.
WHAT IS HAPPENING?
We will be making some improvements to the code that we use to generate
the BGP bogon feeds. These changes are being done to make our service
compliant with the new "extended" allocation and assignment reports
being offered by the Regional Internet Registries (RIRs).
HOW WILL I BE AFFECTED?
Your BGP peering session should not flap during this maintenance window.
However, you may notice our bogon routes get withdrawn and re-announced
several times as a result of internal changes we are making. When the
maintenance window is complete the number of routes you receive over
your peering session should be as follows:
IPv4 Bogons: approximately 3,300 routes
IPv6 Bogons: approximately 44,000 routes
DO I NEED TO MAKE ANY CHANGES ON MY SIDE?
No. None of the parameters for the BGP peering sessions will be
changing. The only setting you may need to adjust is if you have
configured a prefix limit for the number of routes you'll accept from
us. However, since the number of advertised routes is decreasing even
this change is likely unnecessary.
WHY ARE YOU DOING THIS?
The new RIR extended allocation reports make some minor changes to the
status definitions for network resources. All IP resources are now
defined as one of the following:
The meaning of these definitions can be found here:
We are updating our software to use the new extended reports for
tracking RIR allocations. Under the new system, we will only announce
prefixes that are marked 'available' as bogons, along with special
netblocks that are identified in RFC 3330, RFC 4291 and similar
documents. Because this definition is more strict than what we used for
the previous report format the overall number of bogon routes will
decrease. It will also make the chances of accidentally identifying an
allocated prefix as 'bogon' much less likely.
WHO DO I CONTACT IF I HAVE QUESTIONS?
You can reach us at support at cymru.com or by any of the methods listed at
Thank you for participating in the bogon feed project and for your
- --- snip snip ---
We're a bit past our change window, and my apologies for that. We're
almost at the finish line, however, so I'll beg your indulgences while
we wind it up.
Thank you as always for your patience and support!
Rabbi Rob Thomas
"Does this augment or diminish human liberty?" - William F. Buckley
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