Comment 2 for bug 1257875

Additional info: when I ping the instance (10.4.128.2) from the host I run openstack on (localhost.localdomain, 192.168.126.142) I do see arp request packets on both br100 and vnet0

# tcpdump -i br100 arp
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on br100, link-type EN10MB (Ethernet), capture size 65535 bytes
19:49:23.293070 ARP, Request who-has 10.4.128.2 tell localhost.localdomain, length 28
19:49:24.295030 ARP, Request who-has 10.4.128.2 tell localhost.localdomain, length 28
19:49:25.297188 ARP, Request who-has 10.4.128.2 tell localhost.localdomain, length 28
^C
3 packets captured
3 packets received by filter
0 packets dropped by kernel
# tcpdump -i vnet0 arp
tcpdump: WARNING: vnet0: no IPv4 address assigned
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on vnet0, link-type EN10MB (Ethernet), capture size 65535 bytes
19:49:35.404475 ARP, Request who-has 10.4.128.2 tell localhost.localdomain, length 28
19:49:36.406490 ARP, Request who-has 10.4.128.2 tell localhost.localdomain, length 28
19:49:37.409074 ARP, Request who-has 10.4.128.2 tell localhost.localdomain, length 28
^C
3 packets captured
3 packets received by filter
0 packets dropped by kernel