After following the ipchains discussion last week, I decided to kill my
NT sygate machine and start using IPMASQ for my NAT over a cable modem.
Everything's working great, but last night I decided to try the
'semi-strong' ipchians ruleset found in the IPChains HOW TO.
WOW! I was logging all sorts of stuff. So much, that my
/var/log/messages was increasing about 10K/minute. I noticed that most
of the rejected packets were the default input rule, so I turned logging
off, but left it ON for things like spoofing. Now, it seems like I'm
seeing lots of spoofing attacks, or maybe I'm just reading the logs
wrong. Here's a sample from the logs:
Mar 2 13:25:44 kenny kernel: Packet log: input REJECT eth1 PROTO=17
192.168.0.5:137 192.168.0.255:137 L=78 S=0x00 I=53465 F=0x0000 T=128
(#2)
Mar 2 13:25:46 kenny kernel: Packet log: input REJECT eth1 PROTO=17
192.168.0.111:138 192.168.0.255:138 L=239 S=0x00 I=56325 F=0x0000 T=128
(#2)
Mar 2 13:26:10 kenny kernel: Packet log: input REJECT eth1 PROTO=17
192.168.0.112:137 192.168.0.255:137 L=78 S=0x00 I=24902 F=0x0000 T=32
(#2)
Mar 2 13:27:21 kenny kernel: Packet log: input REJECT eth1 PROTO=17
192.168.0.104:137 192.168.0.255:137 L=78 S=0x00 I=13873 F=0x0000 T=128
(#2)
Mar 2 13:27:41 kenny kernel: Packet log: input REJECT eth1 PROTO=17
192.168.0.151:137 192.168.0.255:137 L=78 S=0x00 I=17423 F=0x0000 T=128
(#2)
The #2 rule referred to above is:
ipchains -A input -i $extint -s $intnet -d 0.0.0.0/0 -l -j REJECT
Anyone have know where I can find a good source for interpreting these
logs? Should I be concerned, or am I being overly paranoid?
Thanks.
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Chris Egolf
http://www.ugholf.net ">cegolf@ugholf.net
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