Last I checked "no ip unreachables" breaks PMTUD which can be fine in your environment or cause other serious problems. Vijay Ramcharan -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Lee Sent: April 24, 2009 11:10 To: Marian Ďurkovič Cc: Chris Lane; Richard Gallagher; cisco-nsp Subject: Re: [c-nsp] 3750 High Cpu IP Input
On 4/24/09, Marian Ďurkovič <[email protected]> wrote: > On Fri, Apr 24, 2009 at 10:01:08AM -0400, Lee wrote: >> > These TTL=1 are causing the high CPU. > > Yes, those are not HW switched but punted to CPU in order to generate > TTL_Exceeded ICMP message. Not sure if there's any knob to discard > them silently. I thought that's what "no ip unreachable" was for.. >> Just out of curiousity, would adding "ip multicast ttl-threshold 3" > > Beware, this is real evil. On most switch platforms this will completely > disable HW forwarding of multicast packets and punt them *all* to CPU. oops... shows how much I know <grin> Thanks, Lee _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/ ______________________________________________________________________ This e-mail has been scanned by Verizon Managed Email Content Service, using Skeptic technology powered by MessageLabs. For more information on Verizon Managed Email Content Service, visit http://www.verizonbusiness.com. ______________________________________________________________________ _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
