Date: Wed, 21 Mar 2007 22:08:06 +0100 From: Jon Otterholm <jon.otterholm@ide.resurscentrum.se> To: freebsd-net@freebsd.org Subject: Re: ICMP-floods Message-ID: <46019EB6.6010209@ide.resurscentrum.se> In-Reply-To: <D0ACB868-E4D7-4438-92B5-F3769F7CD31C@mac.com> References: <460060A8.1080109@ide.resurscentrum.se> <65531A6A-7178-48A1-97D0-9DCB4F72E315@mac.com> <4600689C.3080306@ide.resurscentrum.se> <D0ACB868-E4D7-4438-92B5-F3769F7CD31C@mac.com>
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Chuck Swiger wrote: > On Mar 20, 2007, at 4:05 PM, Jon Otterholm wrote: >>>> When setting net.inet.ip.redirect=0 on my routers, the icmp-redirects >>>> disappear, but instead I get a large amount of ICMP-time-exceed >>>> from my >>>> routers. >>> >>> The information you've provided strongly suggests either problems >>> with the netmasks being used, or a routing loop, or some combination >>> of both. >> I have checked netmasks and they are all on the same network. There >> should not be any routing involved in the communication between these >> hosts. > > OK. Care to show a "tcpdump -ntv icmp" illustrating the problem...? :-) Nope :-) I dug a little deeper into this. It seems like my problems are far more extensive than I first expected. I did not mention earlier that all if's are vlan-based sub-intefaces. It seems that if I move admin-if's on my routers to a different physical if than the one with the default route, all weird time-exeed/redir are gone and all traffic on my Nagios-machine are OK. It seems allmost as if my routers can not hold apart inbound traffic destined to different sub-if's on one physical if. Can this be it? I have checked my topology from all around now and I can not find any routing loops. For example: Router1 has it's default route connected to em0.10. With admin-net on em0.20 I get my icmp-floods. Moving admin-net to em1.20 makes the icmp-floods go away. A possible bug in if_vlan? //Jon
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