Date: Mon, 8 Apr 2002 09:34:18 -0500 (CDT) From: Nick Rogness <nick@rogness.net> To: cjclark@alum.mit.edu Cc: "Matthew D. Fuller" <fullermd@over-yonder.net>, Alex Rousskov <rousskov@measurement-factory.com>, freebsd-net@FreeBSD.ORG Subject: Re: Forcing packets to the wire Message-ID: <Pine.BSF.4.21.0204080929280.24265-100000@cody.jharris.com> In-Reply-To: <20020407200631.S70207@blossom.cjclark.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Sun, 7 Apr 2002, Crist J. Clark wrote: > On Sun, Apr 07, 2002 at 08:25:33PM -0500, Nick Rogness wrote: > > [SNIP] > > > > AFAIK, the route to get from 1 interface to the other is not > > through the lo0. I'm not sure if the kernel sends these packets > > across lo0 (internally) or not. But the routing table would > > suggest not. > > It sure looks like they do. I checked before suggesting this. > > $ ifconfig dc0 > dc0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 > inet 192.168.64.60 netmask 0xffffff00 broadcast 192.168.64.255 > inet6 fe80::2c0:f0ff:fe5a:6c0a%dc0 prefixlen 64 scopeid 0x1 > inet 192.168.64.61 netmask 0xffffffff broadcast 192.168.64.61 > ether 00:c0:f0:5a:6c:0a > media: Ethernet autoselect (10baseT/UTP) > status: active > $telnet -s 192.168.64.60 192.168.64.61 > Trying 192.168.64.61... > telnet: connect to address 192.168.64.61: Connection refused > telnet: Unable to connect to remote host > > And I was sniffing the loopback when I did this, > > # tcpdump -n -ilo0 > tcpdump: listening on lo0 > 20:02:34.300094 192.168.64.60.1979 > 192.168.64.61.23: S > 2453490862:2453490862(0) win 65535 <mss 16344,nop,wscale > 1,nop,nop,timestamp 11409532 0> (DF) [tos 0x10] > 20:02:34.300138 192.168.64.61.23 > 192.168.64.60.1979: R 0:0(0) ack > 2453490863 win 0 > > I also put in some ipfw(8) 'count' rules like, > > # ipfw add count ip from 192.168.64.60 to 192.168.64.61 out via lo0 > > And they were hit by these packets. WOW, that's interesting. Thanks for the heads up. Nick Rogness <nick@rogness.net> - Don't mind me...I'm just sniffing your packets To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?Pine.BSF.4.21.0204080929280.24265-100000>