hi guys,

i have been hearing so much about arp poisoning. pls if i may ask what type of attack is this and how do i know that my system is under such attack. lastly, what is the point of action/remedy to prevent such


thanks

Google is your friend. Try it sometime...

http://en.wikipedia.org/wiki/ARP_spoofing <-- first hit on Google.

I'm not trying to be a smart ass here. I'm just trying to enlighten you to the fact that it took less keystrokes for me to do that Google search, which gave many relevant hits, than it did for you to post this query. Searching is good for you!

Have FUN!

May 18 19:00:00 kule8 newsyslog[49864]: logfile turned over due to size>100K
May 18 19:00:00 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:00:01 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:00:06 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:00:07 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:00:10 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:00:10 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:00:15 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:00:16 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:00:21 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:00:22 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:00:29 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:00:32 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:00:36 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:00:38 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:00:42 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:00:44 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:00:45 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:00:46 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:00:51 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:00:53 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:00:54 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:00:56 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:00:57 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:00:59 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:01:00 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:01:02 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:01:05 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:01:08 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:01:08 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:01:11 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:01:11 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:01:14 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:01:14 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:01:17 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:01:17 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:01:20 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:01:24 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:01:26 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:01:29 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:01:29 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:01:35 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:01:35 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:01:41 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:01:41 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:01:44 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:01:47 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:01:47 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:01:50 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:01:56 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:01:57 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:02:00 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:02:00 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:02:03 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:02:06 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:02:06 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:02:09 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:02:15 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:02:18 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:02:22 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:02:24 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:02:30 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:02:31 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0
May 18 19:02:37 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:a9:e3:c3 to 00:30:18:ab:a9:25 on re0
May 18 19:02:41 kule8 kernel: arp: 192.168.1.249 moved from 00:30:18:ab:a9:25 to 00:30:18:a9:e3:c3 on re0

see this :P

You could save even more time by searching this forum for "arp poisoning". You'll get even more relevant info on the first page.

@hackintosh: the first 00:30:18 identify the NIC manufacturer, which I'm showing as Jetway Information Co., Ltd. Could just be coincidence the "hacker" is using the same brand, or you could have a dual NIC mobo and some kind of configuration problem instead of a security problem.