Date: Wed, 12 May 1999 17:58:08 -0700 From: Ludwig Pummer <ludwigp@toy.chip-web.com> To: Kiril Mitev <kiril@ideaglobal.com>, freebsd-questions@freebsd.org Subject: Re: ICMP bandwidth limiter Message-ID: <4.1.19990512175317.00a6ecb0@mail-r> In-Reply-To: <199905121039.LAA24194@idea.co.uk>
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At 03:39 AM 5/12/1999 , Kiril Mitev wrote: >Hi, > >this came up on the console, presumably because >I have the ICMP_BANDLIM options in my kernel: > >icmp-response bandwidth limit 118/100 pps >icmp-response bandwidth limit 106/100 pps >icmp-response bandwidth limit 101/100 pps >icmp-response bandwidth limit 112/100 pps >icmp-response bandwidth limit 120/100 pps >....... > >which sort of raises a few question :-) > >1. is there any way of raising the built-in limit >to, say, 120 (whatever that number means), and if yes, >is there a risk of being "pinged-out" >2. is there any way of catching the IP from which >the flood ping is coming from ? >3. should I ask on -security ? When I upgraded to 3.1-S and looked through the kernel config and saw this, I became interested (mostly because there didn't seem to be any tunable options). I searched the mailing list archives (-questions, -stable, -current, -isp) and found a thread where ICMP_BANDLIM was being discussed. IIRC, it doesn't need to be tunable. ICMP_BANDLIM limits only ICMP error messages, like (i think) port unreachable or network unreachable or something like that (pings are echo messages). The only time (in my considerable short experience with this option enabled) when I saw this come up was when I was doing a nessus port scan of one machine. The machine doing the scanning kept printing these messages. You could probably run tcpdump and friends and see where it's coming from. What would you ask -security ? --Ludwig Pummer ( ludwigp@bigfoot.com ) ICQ UIN: 692441 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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