arpon need eth0 with dhcp,but pppoe cann't get connection if ifup eth0 with dhcp

[yuanwei xu <xuyuanwei@gmail.com>]

Hello,
     I found arp attack under windows,so i installed "arpon" in Debian Squeeze,even if there is no "ip confiction" prompt as windows.
When service arpon is started,it sayed: "ERROR: arpon.c:685 @ eth0: no IPv4 address assigned.",then quit with failure.
    The problem is my pppoe cann't get connection when dhcp was used on eth0 ("nslookup website" will fail).
So in my /etc/network/interface is:
###
auto lo
iface lo inet loopback

auto myisp
iface myisp inet ppp
    provider dsl-provider

allow-hotplug eth0
###

and as a result,the ifconfig output is:

###
eth0      Link encap:Ethernet  HWaddr 00:14:0b:36:0f:e5  
          inet6 addr: fe80::214:bff:fe36:fe5/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:327783 errors:0 dropped:0 overruns:0 frame:0
          TX packets:239219 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:363595254 (346.7 MiB)  TX bytes:20418761 (19.4 MiB)
          Interrupt:23 Base address:0x4800 

ppp0      Link encap:Point-to-Point Protocol  
          inet addr:10.0.0.126  P-t-P:10.0.0.1  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1492  Metric:1
          RX packets:249097 errors:0 dropped:0 overruns:0 frame:0
          TX packets:239183 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3 
          RX bytes:351496310 (335.2 MiB)  TX bytes:15152829 (14.4 MiB)
###

if using "arpon -i ppp0",then it shows:" ERROR: (null) device's datalink is not supported!"

if i start eth0 using dhcp,with ifconfig output below,the arpon can get started rightly,but nslookup failed.

ifconfig output:
###
eth0      Link encap:Ethernet  HWaddr 00:14:0b:36:0f:e5  
          inet addr:192.168.1.213  Bcast:192.168.1.255  Mask:255.255.255.0
          inet6 addr: fe80::214:bff:fe36:fe5/64 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:331384 errors:0 dropped:0 overruns:0 frame:0
          TX packets:239548 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:364022940 (347.1 MiB)  TX bytes:20471884 (19.5 MiB)
          Interrupt:23 Base address:0x4800 

ppp0      Link encap:Point-to-Point Protocol  
          inet addr:10.0.0.126  P-t-P:10.0.0.1  Mask:255.255.255.255
          UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1492  Metric:1
          RX packets:53 errors:0 dropped:0 overruns:0 frame:0
          TX packets:48 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:3 
          RX bytes:8991 (8.7 KiB)  TX bytes:6578 (6.4 KiB)
###

What i concern is how can i use "arpon" with my pppoe connection as there is such a problem.
Is there arp attack concern in linux?