I am experiencing duplicate pings with virtual machines when connected to my network via wireless. I am running Mac OS 10.5.5 with all the updates available up to today (including, rather ominously, an Airport update that came out this late this week)
I have two CentOS 5.2 virtual machines also fully updated. When the adapters are configured to use NAT they work fine. When they are configured to use bridging and are connected to my network via a wired connection they work fine. However, when they are configured to use bridging and are connected to my network via wireless I receive DUP! messages while pinging back and forth. I should note that it does not appear to be affecting network connectivity; I was using the two to work out the ports required for using NFS shares when a firewall is in use and did a quick ping to ensure they were communicating with each other when I discovered this problem. I configured the 'server' and got everything working despite the issue and I'd honestly be none the wiser to the problem aside from the messages from ping...there are definitely no duplicate address on the network (a desktop, the laptop, the two virtual machines, my phone, and my printer; verified all addresses. I have complete control and sole access to the network so I can be 99.99% certain there are not any duplicates)
If it matters the wireless router is a WRT54G2 Firmware 1.0.0.1
(From one CentOS VM to the other)
ping 192.168.1.203
PING 192.168.1.203 (192.168.1.203) 56(84) bytes of data.
64 bytes from 192.168.1.203: icmp_seq=1 ttl=64 time=0.407 ms
64 bytes from 192.168.1.203: icmp_seq=1 ttl=63 time=1.43 ms (DUP!)
64 bytes from 192.168.1.203: icmp_seq=2 ttl=64 time=0.751 ms
64 bytes from 192.168.1.203: icmp_seq=2 ttl=63 time=1.91 ms (DUP!)
64 bytes from 192.168.1.203: icmp_seq=3 ttl=64 time=0.858 ms
64 bytes from 192.168.1.203: icmp_seq=3 ttl=63 time=1.89 ms (DUP!)
64 bytes from 192.168.1.203: icmp_seq=4 ttl=64 time=0.807 ms
64 bytes from 192.168.1.203: icmp_seq=4 ttl=63 time=1.80 ms (DUP!)
64 bytes from 192.168.1.203: icmp_seq=5 ttl=64 time=0.729 ms
64 bytes from 192.168.1.203: icmp_seq=5 ttl=63 time=1.76 ms (DUP!)
From my host OS (Mac OS 10.5.5) to each of the virtual machines
ping 192.168.1.203
PING 192.168.1.203 (192.168.1.203): 56 data bytes
64 bytes from 192.168.1.203: icmp_seq=0 ttl=64 time=1.284 ms
64 bytes from 192.168.1.203: icmp_seq=0 ttl=64 time=5.225 ms (DUP!)
64 bytes from 192.168.1.203: icmp_seq=1 ttl=64 time=0.498 ms
64 bytes from 192.168.1.203: icmp_seq=1 ttl=64 time=1.458 ms (DUP!)
64 bytes from 192.168.1.203: icmp_seq=2 ttl=64 time=0.465 ms
64 bytes from 192.168.1.203: icmp_seq=2 ttl=64 time=1.400 ms (DUP!)
^C
--- 192.168.1.203 ping statistics ---
3 packets transmitted, 3 packets received, +3 duplicates, 0% packet loss
round-trip min/avg/max/stddev = 0.465/1.722/5.225/1.618 ms
macbook:etc jason$ ping 192.168.1.204
PING 192.168.1.204 (192.168.1.204): 56 data bytes
64 bytes from 192.168.1.204: icmp_seq=0 ttl=64 time=0.688 ms
64 bytes from 192.168.1.204: icmp_seq=0 ttl=64 time=2.186 ms (DUP!)
64 bytes from 192.168.1.204: icmp_seq=1 ttl=64 time=0.311 ms
64 bytes from 192.168.1.204: icmp_seq=1 ttl=64 time=1.528 ms (DUP!)
64 bytes from 192.168.1.204: icmp_seq=2 ttl=64 time=0.467 ms
64 bytes from 192.168.1.204: icmp_seq=2 ttl=64 time=1.369 ms (DUP!)
^C
--- 192.168.1.204 ping statistics ---
3 packets transmitted, 3 packets received, +3 duplicates, 0% packet loss
round-trip min/avg/max/stddev = 0.311/1.091/2.186/0.662 ms