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</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'>Because you often can’t upgrade the control plane and in general, you don’t expect your control plane to handle your link capacity. The only exception to this is software-based routers which I assume we’re not talking about here.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D;mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> AusNOG [mailto:ausnog-bounces@lists.ausnog.net] <b>On Behalf Of </b>Geordie Guy<br><b>Sent:</b> Wednesday, 21 May 2014 10:49 AM<br><b>To:</b> Luke Iggleden<br><b>Cc:</b> <ausnog@lists.ausnog.net><br><b>Subject:</b> Re: [AusNOG] network security Question<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>If your links are big enough to exhaust your control plane CPU why would you limit ICMP instead of upgrading your control plane CPU to match your link capacity?<o:p></o:p></p></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><o:p> </o:p></p><div><p class=MsoNormal>On Wed, May 21, 2014 at 10:41 AM, Luke Iggleden <<a href="mailto:luke+ausnog@sisgroup.com.au" target="_blank">luke+ausnog@sisgroup.com.au</a>> wrote:<o:p></o:p></p><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-right:0cm'><p class=MsoNormal>Rate limiting router control planes is definitely required though if your links are big enough to kill your control plane cpu.<br><br>I think police 5Mbit/s of ICMP to a border router control plane is acceptable.<br><br>-- <br>Luke Iggleden<o:p></o:p></p><div><p class=MsoNormal><br><br><br>On 21/05/2014 10:21 am, Chris Chaundy wrote:<o:p></o:p></p></div><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-right:0cm'><div><p class=MsoNormal>If you are getting flooded with icmp, blocking/rate-limiting at your<br>border is pretty well pointless as the damage is already done - your<br>link is toast and the attackers don't give a damn about replies.<br><br>And talking about DNS, don't even get started on NTP!!! SIgh...<br><br><br>On Wed, May 21, 2014 at 10:15 AM, Joshua D'Alton <<a href="mailto:joshua@railgun.com.au" target="_blank">joshua@railgun.com.au</a><o:p></o:p></p></div><div><p class=MsoNormal><mailto:<a href="mailto:joshua@railgun.com.au" target="_blank">joshua@railgun.com.au</a>>> wrote:<br><br> Some places do this, Linode I believe in some locations (or perhaps<br> their carriers/DCs?), just have to remember said hop (XYZ router(s)<br> will always have some loss (usually 30%, its consistent). And what<br> level, well presumably layer 3 ACLs?<br><br><br> On Wed, May 21, 2014 at 10:08 AM, Alex Samad - Yieldbroker<o:p></o:p></p></div><div><p class=MsoNormal> <<a href="mailto:Alex.Samad@yieldbroker.com" target="_blank">Alex.Samad@yieldbroker.com</a> <mailto:<a href="mailto:Alex.Samad@yieldbroker.com" target="_blank">Alex.Samad@yieldbroker.com</a>>> wrote:<br><br> With the icmp, I was more thinking about rate limiting, all nice<br> to allow it through, but I also rate limit. Haven't got any<br> shaping on, but I would be de prioritising a lot of icmp<br><br> Just wondering what sort of level do (if they do) rate limit icmp to<br><br><br> _______________________________________________<br> AusNOG mailing list<o:p></o:p></p></div><p class=MsoNormal> <a href="mailto:AusNOG@lists.ausnog.net" target="_blank">AusNOG@lists.ausnog.net</a> <mailto:<a href="mailto:AusNOG@lists.ausnog.net" target="_blank">AusNOG@lists.ausnog.net</a>><br> <a href="http://lists.ausnog.net/mailman/listinfo/ausnog" target="_blank">http://lists.ausnog.net/mailman/listinfo/ausnog</a><o:p></o:p></p><div><p class=MsoNormal style='margin-bottom:12.0pt'><br><br><br><br><br>_______________________________________________<br>AusNOG mailing list<br><a href="mailto:AusNOG@lists.ausnog.net" target="_blank">AusNOG@lists.ausnog.net</a><br><a href="http://lists.ausnog.net/mailman/listinfo/ausnog" target="_blank">http://lists.ausnog.net/mailman/listinfo/ausnog</a><o:p></o:p></p></div></blockquote><div><div><p class=MsoNormal><br><br>_______________________________________________<br>AusNOG mailing list<br><a href="mailto:AusNOG@lists.ausnog.net" target="_blank">AusNOG@lists.ausnog.net</a><br><a href="http://lists.ausnog.net/mailman/listinfo/ausnog" target="_blank">http://lists.ausnog.net/mailman/listinfo/ausnog</a><o:p></o:p></p></div></div></blockquote></div><p class=MsoNormal><o:p> </o:p></p></div></div></body></html>