Date: Mon, 22 Sep 2003 13:38:30 +0300 From: "Pertti Kosunen" <pertti.kosunen@kolumbus.fi> To: "Kris Kennaway" <kris@obsecurity.org> Cc: freebsd-stable@freebsd.org Subject: Re: [snort] BAD-TRAFFIC loopback traffic 4.9-PRE Message-ID: <00b801c380f5$aaef7af0$0b00000a@arenanet.fi> References: <030501c37f99$4beb9500$0b00000a@arenanet.fi> <20030920210527.GB38264@rot13.obsecurity.org>
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>> What could cause this loopback traffic? > > Forged source address on a network with no egress filtering. > > Kris Ok i put the ipfw on with the default simple mode. ipfw -a l 00100 0 0 allow ip from any to any via lo0 00200 0 0 deny ip from any to 127.0.0.0/8 00300 0 0 deny ip from 127.0.0.0/8 to any ... Still get this: tcpdump: listening on xl0 12:51:15.736517 0:90:1a:40:1f:db 0:50:da:ca:61:e9 0800 60: 127.0.0.1.80 > out.ip.1165: R 0:0(0) ack 1416364033 win 0 12:51:19.092168 0:90:1a:40:1f:db 0:50:da:ca:61:e9 0800 60: 127.0.0.1.80 > out.ip.1284: R 0:0(0) ack 72679425 win 0 12:52:32.717702 0:90:1a:40:1f:db 0:50:da:ca:61:e9 0800 60: 127.0.0.1.80 > out.ip.1667: R 0:0(0) ack 1243086849 win 0 0:90:1a:40:1f:db Is default gateways (ISP) mac address, xl0 0:50:da:ca:61:e9 is my outside net card. Is this normal traffic and what i should check next?
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