我遇到了一个很奇怪的问题，我想和你分享。也许你会帮助我对正在发生的事情提出一些想法。
KVM 驱动的主机上有 3 个虚拟机。实际上有大约 50 台虚拟机，但它们都运行良好，尽管这 3 台虚拟机的行为有点不寻常。
下图说明了这 3 个 VM 和它们之间的 2 个链接：
当一切正常时，这些会话之间的 TCP 会话（“GET / HTTP/1.0” - “HTTP 200 OK”）如下所示：
00:58:43.885118 IP 192.168.111.2.55480 > 192.168.113.2.http: Flags [S], seq 926382744, win 14600, options [mss 1460,sackOK,TS val 277997 ecr 0,nop,wscale 7], length 0
00:58:43.885380 IP 192.168.113.2.http > 192.168.111.2.55480: Flags [S.], seq 1849545379, ack 926382745, win 14480, options [mss 1460,sackOK,TS val 3702103 ecr 277997,nop,wscale 7], length 0
00:58:43.885957 IP 192.168.111.2.55480 > 192.168.113.2.http: Flags [.], ack 1, win 115, options [nop,nop,TS val 277998 ecr 3702103], length 0
00:58:43.886000 IP 192.168.111.2.55480 > 192.168.113.2.http: Flags [P.], seq 1:213, ack 1, win 115, options [nop,nop,TS val 277998 ecr 3702103], length 212
00:58:43.886061 IP 192.168.113.2.http > 192.168.111.2.55480: Flags [.], ack 213, win 122, options [nop,nop,TS val 3702104 ecr 277998], length 0
00:58:43.922286 IP 192.168.113.2.http > 192.168.111.2.55480: Flags [P.], seq 1:372, ack 213, win 122, options [nop,nop,TS val 3702140 ecr 277998], length 371
00:58:43.922335 IP 192.168.113.2.http > 192.168.111.2.55480: Flags [F.], seq 372, ack 213, win 122, options [nop,nop,TS val 3702140 ecr 277998], length 0
00:58:43.923150 IP 192.168.111.2.55480 > 192.168.113.2.http: Flags [.], ack 372, win 123, options [nop,nop,TS val 278035 ecr 3702140], length 0
00:58:43.923622 IP 192.168.111.2.55480 > 192.168.113.2.http: Flags [F.], seq 213, ack 373, win 123, options [nop,nop,TS val 278036 ecr 3702140], length 0
00:58:43.923671 IP 192.168.113.2.http > 192.168.111.2.55480: Flags [.], ack 214, win 122, options [nop,nop,TS val 3702142 ecr 278036], length 0
好的，到目前为止一切都很好。
然后我们保存 pfSense 配置，销毁这个 VM，创建一个新的，从头开始安装 pfSense 并从备份文件中恢复其配置。
这是我们之后看到的：
00:46:39.218193 IP 192.168.111.2.51674 > 192.168.113.2.http: Flags [S], seq 3622924060, win 14600, options [mss 1460,sackOK,TS val 674608862 ecr 0,nop,wscale 7], length 0
00:46:39.218316 IP 192.168.113.2.http > 192.168.111.2.51674: Flags [S.], seq 152904245, ack 3622924061, win 14480, options [mss 1460,sackOK,TS va l 2977436 ecr 674608862,nop,wscale 7], length 0
00:46:39.218570 IP 192.168.111.2.51674 > 192.168.113.2.http: Flags [.], ack 1, win 115, options [nop,nop,TS val 674608862 ecr 2977436], length 0
00:46:40.417623 IP 192.168.113.2.http > 192.168.111.2.51674: Flags [S.], seq 152904245, ack 3622924061, win 14480, options [mss 1460,sackOK,TS val 2978636 ecr 674608862,nop,wscale 7], length 0
00:46:40.417947 IP 192.168.111.2.51674 > 192.168.113.2.http: Flags [.], ack 1, win 115, options [nop,nop,TS val 674610062 ecr 2977436], length 0
00:46:43.158907 IP 192.168.111.2.51674 > 192.168.113.2.http: Flags [P.], seq 1:17, ack 1, win 115, options [nop,nop,TS val 674612803 ecr 2977436], length 16
00:46:43.360103 IP 192.168.111.2.51674 > 192.168.113.2.http: Flags [P.], seq 1:17, ack 1, win 115, options [nop,nop,TS val 674613004 ecr 2977436], length 16
00:46:43.761787 IP 192.168.111.2.51674 > 192.168.113.2.http: Flags [P.], seq 1:17, ack 1, win 115, options [nop,nop,TS val 674613406 ecr 2977436], length 16
00:46:44.565890 IP 192.168.111.2.51674 > 192.168.113.2.http: Flags [P.], seq 1:17, ack 1, win 115, options [nop,nop,TS val 674614210 ecr 2977436], length 16
00:46:46.174039 IP 192.168.111.2.51674 > 192.168.113.2.http: Flags [P.], seq 1:17, ack 1, win 115, options [nop,nop,TS val 674615818 ecr 2977436], length 16
00:46:49.389921 IP 192.168.111.2.51674 > 192.168.113.2.http: Flags [P.], seq 1:17, ack 1, win 115, options [nop,nop,TS val 674619034 ecr 2977436], length 16
00:46:51.753723 IP 192.168.113.2.http > 192.168.111.2.51672: Flags [F.], seq 1, ack 1, win 114, options [nop,nop,TS val 2989972 ecr 674560137], length 0
00:46:55.821824 IP 192.168.111.2.51674 > 192.168.113.2.http: Flags [P.], seq 1:17, ack 1, win 115, options [nop,nop,TS val 674625466 ecr 2977436], length 16
00:46:57.221625 IP 192.168.113.2.http > 192.168.111.2.51672: Flags [F.], seq 1, ack 1, win 114, options [nop,nop,TS val 2995440 ecr 674560137], length 0
00:47:08.157575 IP 192.168.113.2.http > 192.168.111.2.51672: Flags [F.], seq 1, ack 1, win 114, options [nop,nop,TS val 3006376 ecr 674560137], length 0
00:47:08.685886 IP 192.168.111.2.51674 > 192.168.113.2.http: Flags [P.], seq 1:17, ack 1, win 115, options [nop,nop,TS val 674638330 ecr 2977436], length 16
00:47:30.029609 IP 192.168.113.2.http > 192.168.111.2.51672: Flags [F.], seq 1, ack 1, win 114, options [nop,nop,TS val 3028248 ecr 674560137], length 0
00:47:34.413785 IP 192.168.111.2.51674 > 192.168.113.2.http: Flags [P.], seq 1:17, ack 1, win 115, options [nop,nop,TS val 674664058 ecr 2977436], length 16
00:47:40.478757 IP 192.168.113.2.http > 192.168.111.2.51674: Flags [F.], seq 1, ack 1, win 114, options [nop,nop,TS val 3038697 ecr 674610062], length 0
00:47:34.413785 IP 192.168.111.2.51674 > 192.168.113.2.http: Flags [P.], seq 1:17, ack 1, win 115, options [nop,nop,TS val 674664058 ecr 2977436], length 16
00:47:40.478757 IP 192.168.113.2.http > 192.168.111.2.51674: Flags [F.], seq 1, ack 1, win 114, options [nop,nop,TS val 3038697 ecr 674610062], length 0
00:47:40.479216 IP 192.168.111.2.51674 > 192.168.113.2.http: Flags [FP.], seq 17:19, ack 2, win 115, options [nop,nop,TS val 674670123 ecr 3038697], length 2
00:47:45.946604 IP 192.168.113.2.http > 192.168.111.2.51674: Flags [F.], seq 1, ack 1, win 114, options [nop,nop,TS val 3044165 ecr 674610062], length 0
00:47:45.946979 IP 192.168.111.2.51674 > 192.168.113.2.http: Flags [.], ack 2, win 115, options [nop,nop,TS val 674675591 ecr 3044165,nop,nop,sack 1 {1:2}], length 0
看起来……我不知道，就像他们没有听到对方的声音一样。他们可以互相 ping 通，甚至可以互相交互，但看起来他们只是忽略了一些数据包。
两个 VM 显示相同，因此 pfSense 不会丢弃任何数据包。尽管那里的数据包似乎出现了问题。就像他们被什么东西弄坏了一样。
这是我无法理解的事情，真的。如果您与我分享任何想法，那将是非常棒的。
在此先感谢大家！
重新启动 pfsense VM 后它可以工作吗？
根据他们的 VirtIO 文档here
我假设如果您只是加载配置，则与选中该框相同，但仍需要手动重新启动。
您的行为也符合引用的错误。这是由于未正确计算 TCP 数据包的校验和导致数据包在接收方看来已损坏并被丢弃，这就是 ICMP 数据包（如 ping）工作正常的原因。