nanog mailing list archives

Re: Automate Peering Maintenance


From: Rafael Rodriguez <packetjockey () gmail com>
Date: Thu, 19 Jan 2012 23:26:07 -0500

Hi Mauricio, thanks for the reply.

I believe there are quite a few folks who automate their peering up keep
with the help of the data contained within the IRRs.  With the IRRs
providing a mechanism for validating routing information and RPSL providing
a common language for describing routing policy - automating the creation
of prefix and AS-Path filters for peering sessions becomes attractive.
Check out http://www.irr.net/docs/faq.html for additional reasons for using
IRR data to generate routing policy.

IRRToolSet is a tool that can create router configurations based on IRR
data.  The portion I'm trying to figure out is the 'pushing' of these
configurations.  From what I gather, it seems that this is usually
something thats homegrown.  Anyone willing to share their homegrown tools?
 :)

Cheers,
RR


On Sat, Jan 7, 2012 at 6:20 PM, Rodriguez, Mauricio
<mrodriguez () fletnet com>wrote:

Rafael,

Hello!  Nice to see you post on the list...

This sounds like a nice idea.  Do you know of anyone that's currently
running such an automated system?  If you end up finding something, or
rolling it yourself, I would suggest being careful with his approach.
 You're assuming that your peers are actually keeping the IRR records up to
date or that the information contained therein is appropriate for
non-transit peering sessions.  If you have the right leverage, perhaps you
can make that a condition for peering.  If you're manually keeping
prefix-list filters for each of your peers now, consider the return on that
level of detailed configuration.  Is the risk mitigated really worth the
overhead?

I would recommend that you keep your peer filters as simple as possible.
 Inbound, certainly filter bogons, martians, your own prefixes, and any
prefixes received from other peers.  Try using communities vs. individual
prefix entries as much as possible.  Perhaps enforce the peer ASN with an
AS Path filter on the leading ASN on each prefix received.  If you're
concerned about FIB size explosion, decide on a bit boundary for prefixes
to be accepted and filter on that.  Certainly agree on a prefix-limit with
your peer and configure that on the peering session.  You may have to be
diligent on monitoring sessions that drop due to prefix-limit violations
(SNMP Traps, syslog) and follow up to correct those as needed, since most
peers won't keep you informed on changes in their quantity of advertised
prefixes.  Juniper routers can be configured to send warnings on certain
thresholds so you can catch normal growth vs. a fat-fingered configuration
by a peer.  You can then take care of those proactively before sessions
start dropping.

Outbound, don't let anything out other than your own prefixes or those
advertised to you by your customers.  Otherwise, you may be providing free
transit to your upstreams and other peers.

Just my $0.02, others will likely disagree and recommend that you keep
your prefix filters in place.  I digress if there's some BCP out there that
I don't know about that indicates that prefix filters be used in this case.

Regards,
Mauricio Rodriguez
Owner / Principal Engineer
Fletnet Network Engineering

Mauricio.Rodriguez () fletnet com
http://www.fletnet.com

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