-----Original Message----- From: ML [mailto:ml@kenweb.org] Sent: Thursday, November 25, 2010 4:26 PM To: nanog@nanog.org Subject: Cogent announcing more specific prefixes?

Anyone else get alerts from their BGP monitoring system (In my case Cyclops) saying Cogent briefly announced some more specific prefixes?

AS path as reported by Cyclops: 7575 46135 174 174

/20s broken into /23s /23s became /24s

Also saw alerts for one to one (/23 announced has /23)

All alerts had a timestamp of: 2010-11-25 12:01:12 UTC CONFIDENTIAL: This e-mail, including its contents and attachments, if any, are confidential. It is neither an offer to buy or sell, nor a solicitation of an offer to buy or sell, any securities or any related financial instruments mentioned in it. If you are not

We received Cyclops alerts for one of our /24's. It claimed that the prefix was being announced by a provider in Hong Kong. Our alerts fired between 10:36:30 and 10:40:36 UTC today, 2010-11-25. The longest time period that any alert was active was 2m 58s. All appears to be well at this moment; the prefix is not being announced by that provider according to routeviews.org. It is highly unusual for us to receive alerts. We have only 5x /24 networks being monitored. Given that you received similar alerts less than 1.5 hr later, I wonder if this was a systemic problem. -Brian Knight Sr. Network Engineer Mizuho Securities USA Inc http://www.mizuho-sc.com/ * Please note that all NANOG list members and archive readers may consider themselves Recipients of this message, in reference to the appended disclaimer. (I don't add it myself and can't control it, sorry.) the named recipient please notify the sender and immediately delete it. You may not disseminate, distribute, or forward this e-mail message or disclose its contents to anybody else. Unless otherwise indicated, copyright and any other intellectual property rights in its contents are the sole property of Mizuho Securities USA Inc. E-mail transmission cannot be guaranteed to be secure or error-free. The sender therefore does not accept liability for any errors or omissions in the contents of this message which arise as a result of e-mail transmission. If verification is required please request a hard-copy version. Although we routinely screen for viruses, addressees should check this e-mail and any attachments for viruses. We make no representation or warranty as to the absence of viruses in this e-mail or any attachments. Please note that to ensure regulatory compliance and for the protection of our customers and business, we may monitor and read e-mails sent to and from our server(s). #####################################################################################