nmap does not work on host attached tap devices

[z1]

hi i have a virtualbox installed on a debian/testing

i have a win32 xp guest system.

The host has a tap0 device with 192.168.30.1 ip address the guest has a host interface under 192.168.30.2 attached to tap0

i can ping the guest from the host and the host from the guest

ping 192.168.30.2
PING 192.168.30.2 (192.168.30.2) 56(84) bytes of data.
64 bytes from 192.168.30.2: icmp_seq=1 ttl=128 time=3.02 ms

but if i try to nmap the guest from the host it does not work (even with -PN)

nmap -v -A 192.168.30.2

Starting Nmap 4.62 ( http://nmap.org ) at 2008-12-26 14:22 CET
Initiating ARP Ping Scan at 14:22
Scanning 192.168.30.2 [1 port]
Completed ARP Ping Scan at 14:22, 0.21s elapsed (1 total hosts)
Read data files from: /usr/share/nmap
Note: Host seems down. If it is really up, but blocking our ping probes, try -PN
Nmap done: 1 IP address (0 hosts up) scanned in 0.287 seconds
           Raw packets sent: 2 (84B) | Rcvd: 0 (0B)

i can not identify exactly the problem. but if i tcpdump on tap0 i noticed a strange behavior on arp requests

14:10:24.471499 arp who-has 192.168.30.2 tell 192.168.30.1
14:10:24.471749 00:02:08:00:27:1c (oui Unknown) > 00:01:08:00:06:04 (oui Unknown), ethertype Unknown (0xa9db), length 46: 
	0x0000:  c0a8 1e02 c205 a87b 714f c0a8 1e01 804b  .......{qO.....K
	0x0010:  2910 0001 0000 0000 0001 2046 4845 5046  )..........FHEPF

i did not used virtualbox for a while as i was waiting for some feature from that version but i m pretty sure that nmap worked like a charm in the 2.0 series.

[z1]

i switched back to 2.0 and nmap works fine , i think there is really a problem with the new network stack when using tap devices

[Aleksey Ilyushin]

I guess this issue is obsolete. Disagree, anyone?