Mac duplication problem on lan

[NetSpy]

reetings......

arp -n | grep -iv inc |grep -iv addre | sort | more
echo
echo ===============================
echo Online Users `arp -n | grep -iv inc |grep -iv addre| wc -l`
echo Total Allowed Users `cat /home/scripts/allowed.macs | grep -v '^\ '|wc -l`


Code:

10.100.11.21 ether 00:B0:D0:8A:74:63 C eth1
10.100.11.25 ether 00:B0:D0:8A:74:63 C eth1
10.100.11.4 ether 00:19:D1:3F:A4:C9 C eth1
10.100.11.8 ether 00:B0:D0:8A:74:63 C eth1
10.100.12.104 ether 00:B0:D0:8A:74:63 C eth1
10.100.12.106 ether 00:B0:D0:8A:74:63 C eth1
10.100.12.118 ether 00:B0:D0:8A:74:63 C eth1
10.100.12.128 ether 00:B0:D0:8A:74:63 C eth1
10.100.12.12 ether 00:50:04:80:58:79 C eth1
10.100.12.164 ether 00:B0:D0:8A:74:63 C eth1
10.100.12.170 ether 00:B0:D0:8A:74:63 C eth1
10.100.12.80 ether 00:B0:D0:8A:74:63 C eth1
10.100.12.82 ether 00:B0:D0:8A:74:63 C eth1
10.100.12.89 ether 00:B0:D0:8A:74:63 C eth1
10.100.12.93 ether 00:B0:D0:8A:74:63 C eth1
10.100.12.97 ether 00:B0:D0:8A:74:63 C eth1
10.100.13.16 ether 00:16:76:C5:2F:8B C eth1
10.100.1.31 ether 00:A0:C9:DF:30:F0 C eth1
10.100.13.22 ether 00:B0:D0:8A:74:63 C eth1
10.100.13.25 ether 00:C0:26:74:22:50 C eth1
10.100.13.26 ether 00:B0:D0:44:08:93
10.100.16.175 ether 00:01:03:12:FA:F4 C eth1
10.100.16.46 ether 00:B0:D0:5E:93:78 C eth1
10.100.17.30 ether 00:11:11:47:73:01 C eth1
10.100.17.33 ether 00:50:DA:90:D4:63 C eth1
10.100.17.3 ether 00:60:08:AD:B3:F3 C eth1
10.100.17.45 ether [/b]00:B0:D0:8A:74:63 [/b] C eth1
10.100.17.50 ether 00:B0:D0:8A:74:63 C eth1
10.100.17.52 ether 00:50:04:CF:6A:BC C eth1
10.100.17.55 ether 00:50:BF:95:D8:59 C eth1
10.100.17.56 ether 00:C0:4F:60:3F:F7 C eth1
10.100.18.17 ether 00:B0:D0:8A:74:63 C eth1
10.100.18.20 ether 00:30:BD:C1:64:6D C eth1
10.100.18.23 ether 00:B0:D0:8A:74:63 C eth1
10.100.18.25 ether 00:B0:D0:8A:74:63 C eth1
10.100.18.27 ether 00:08:C7:49:57:43 C eth1
10.100.18.38 ether 00:A0:24:AC:27:7E C eth1
10.100.18.39 ether 00:B0:D0:8A:74:63 C eth1
10.100.18.52 ether 4C:00:10:75:46:DF C eth1
10.100.18.57 ether 00:B0:D0:B2:3B:F8 C eth1
10.100.18.5 ether 00:04:AC:98:1A:5A C eth1
10.100.18.60 ether 00:C0:26:25:33:8E C eth1
10.100.18.64 ether 00:15:F2:BA:51:5F C eth1
10.100.18.67 ether 00:0A:E4:C3:0B:AD C eth1


Im getting strage results i run the scripts,it shows me my users list those are online but each user mac should be different for other as i know MAC is a unique.I could not figure it out does any one have any idea reagarding this issue.


Regards
Net_Spy

[stevea]

Yeah - this is easy. 1 interface = one MAC , *but* one interface can have many IP addresses (some practical limit like 4k I think).

I assume that
10.100.11.21 ether 00:B00:8A:74:63 C eth1
10.100.11.25 ether 00:B00:8A:74:63 C eth1
is one interface with two IPs.

You can add a second (or 44th) IP to a local interface with a command like
# ip addr add 10.100.11.25/24 dev eth1