情况：
DomU：Debian SID
/etc/网络/接口
auto eth0
iface eth0 inet static
address x.x.x.55
gateway x.x.x.49
netmask 255.255.255.255
pointopoint x.x.x.49
Ping DomU -> xxx49 (又名 Dom0)
PING x.x.x.49 (x.x.x.49) 56(84) bytes of data.
64 bytes from x.x.x.49: icmp_req=1 ttl=64 time=0.107 ms
Ping DomU->8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
^C
--- 8.8.8.8 ping statistics ---
34 packets transmitted, 0 received, 100% packet loss, time 33263ms
tcpdump -Kn
21:03:30.316328 IP x.x.x.55 > 8.8.8.8: ICMP echo request, id 4904, seq 3, length 64
21:03:31.324344 IP x.x.x.55 > 8.8.8.8: ICMP echo request, id 4904, seq 4, length 64
21:03:32.332338 IP x.x.x.55 > 8.8.8.8: ICMP echo request, id 4904, seq 5, length 64
21:03:33.340323 IP x.x.x.55 > 8.8.8.8: ICMP echo request, id 4904, seq 6, length 64
21:03:34.348343 IP x.x.x.55 > 8.8.8.8: ICMP echo request, id 4904, seq 7, length 64
Dom0：带有 Xen 4.1 的 Debian Wheezy
/etc/网络/接口
auto eth0
iface eth0 inet static
address x.x.x.49
gateway x.x.x.33
netmask 255.255.255.255
pointopoint x.x.x.33
sysctl -a
net.ipv4.conf.eth0.forwarding = 1
net.ipv4.conf.eth0.proxy_arp = 1
net.ipv6.conf.eth0.forwarding = 1
net.ipv4.conf.vif1/0.proxy_arp = 1
iptables -L -n（vif-route 自动添加的规则）
Chain INPUT (policy ACCEPT)
target prot opt source destination
Chain FORWARD (policy ACCEPT)
target prot opt source destination
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 PHYSDEV match --physdev-out vif1.0 --physdev-is-bridged
ACCEPT udp -- 0.0.0.0/0 0.0.0.0/0 PHYSDEV match --physdev-in vif1.0 --physdev-is-bridged udp spt:bootpc dpt:bootps
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 PHYSDEV match --physdev-out vif1.0 --physdev-is-bridged
ACCEPT all -- x.x.x.55 0.0.0.0/0 PHYSDEV match --physdev-in vif1.0 --physdev-is-bridged
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
cat /etc/xen/xend-config.sxp | grep -e 脚本
# (network-script network-bridge)
# (network-script 'network-bridge netdev=eth1')
# (network-script 'network-bridge bridge=<name>')
#(vif-script vif-bridge)
(network-script network-route)
(vif-script vif-route)
#(network-script network-nat)
#(vif-script vif-nat)
#(resource-label-change-script '')
Ping Dom0 -> DomU
PING x.x.x.55 (x.x.x.55) 56(84) bytes of data.
64 bytes from x.x.x.55: icmp_req=1 ttl=64 time=0.148 ms
tcpdump -Kn | grep 55
21:01:36.545890 IP x.x.x.55 > 8.8.8.8: ICMP echo request, id 4880, seq 4, length 64
21:01:36.551504 IP 8.8.8.8 > x.x.x.55: ICMP echo reply, id 4880, seq 4, length 64
21:01:37.545838 IP x.x.x.55 > 8.8.8.8: ICMP echo request, id 4880, seq 5, length 64
21:01:37.550473 IP 8.8.8.8 > x.x.x.55: ICMP echo reply, id 4880, seq 5, length 64
问题
为什么 Dom0 没有将传入的 TCP 包转发到我的 DomU？
答案1
解决方案
事实证明，上述所有设置都是完全正确。问题是，我的主机提供商为附加 IP 分配了一个专用 MAC 地址。因此 Dom0 立即丢弃了该包，因为它认为这不是自己的包。
删除这个虚拟 MAC 之后，数据包就被完美接受并路由到整个系统。
所以
如果你在互联网以太网设备上遇到奇怪的数据包丢失（eth0就我的情况而言），请确保其他一切都正确，并且确保 MAC 地址与您的主地址相同，即eth0！