Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!amdcad!ames!mailrus!tut.cis.ohio-state.edu!triceratops.cis.ohio-state.edu!karl From: karl@triceratops.cis.ohio-state.edu (Karl Kleinpaste) Newsgroups: comp.protocols.tcp-ip Subject: Re: ICMP's & IP src addrs Message-ID: <21838@tut.cis.ohio-state.edu> Date: 15 Sep 88 17:11:43 GMT References: <23634@hi.unm.edu> <8809151450.AA23101@ucbvax.Berkeley.EDU> Sender: news@tut.cis.ohio-state.edu Lines: 71 In-reply-to: tmallory@PARK-STREET.BBN.COM's message of 15 Sep 88 13:04:17 GMT tmallory@park-street.bbn.com writes: > a `ping {-t,-n,-i,} 129.24.15.255' sometimes yields 129.24.15.255 as > the src IP address on the packet that is being returned... Flame: An ICMP echo to a broadcast address should get no response! What an incredibly obnoxious thing to do! This looked just too tempting, so I headed off to one of our Sun-3/180 servers (SunOS 3.5.1) to see what would happen if I abused its client subnet (12 Sun3/50 clients) in this way. The result was just mighty entertaining - the `packet loss' statistic is easily the best part, followed closely by the claimed IP address... Script started on Thu Sep 15 12:06:42 1988 [12] [12:06pm] tree:/dino0/karl> ping -s 128.146.28.255 PING 128.146.28.255: 56 data bytes 64 bytes from 128.146.28.255: icmp_seq=0. time=0. ms 64 bytes from 128.146.28.255: icmp_seq=0. time=0. ms 64 bytes from 128.146.28.255: icmp_seq=0. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=0. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=0. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=0. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=0. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=0. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=0. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=0. time=40. ms 64 bytes from 128.146.28.255: icmp_seq=0. time=40. ms 64 bytes from 128.146.28.255: icmp_seq=0. time=40. ms 64 bytes from 128.146.28.255: icmp_seq=1. time=0. ms 64 bytes from 128.146.28.255: icmp_seq=1. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=1. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=1. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=1. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=1. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=1. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=1. time=40. ms 64 bytes from 128.146.28.255: icmp_seq=1. time=40. ms 64 bytes from 128.146.28.255: icmp_seq=1. time=40. ms 64 bytes from 128.146.28.255: icmp_seq=1. time=40. ms 64 bytes from 128.146.28.255: icmp_seq=1. time=40. ms 64 bytes from 128.146.28.255: icmp_seq=2. time=0. ms 64 bytes from 128.146.28.255: icmp_seq=2. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=2. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=2. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=2. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=2. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=2. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=2. time=40. ms 64 bytes from 128.146.28.255: icmp_seq=2. time=40. ms 64 bytes from 128.146.28.255: icmp_seq=2. time=40. ms 64 bytes from 128.146.28.255: icmp_seq=2. time=40. ms 64 bytes from 128.146.28.255: icmp_seq=2. time=40. ms 64 bytes from 128.146.28.255: icmp_seq=3. time=0. ms 64 bytes from 128.146.28.255: icmp_seq=3. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=3. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=3. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=3. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=3. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=3. time=20. ms 64 bytes from 128.146.28.255: icmp_seq=3. time=40. ms 64 bytes from 128.146.28.255: icmp_seq=3. time=40. ms 64 bytes from 128.146.28.255: icmp_seq=3. time=40. ms 64 bytes from 128.146.28.255: icmp_seq=3. time=40. ms 64 bytes from 128.146.28.255: icmp_seq=3. time=40. ms ^C ----128.146.28.255 PING Statistics---- 4 packets transmitted, 48 packets received, -1100% packet loss round-trip (ms) min/avg/max = 0/25/40 [13] [12:06pm] tree:/dino0/karl> exit script done on Thu Sep 15 12:07:01 1988