我有一个问题。我的主板是 Supermicro 的 X11SBA-LN4F。有 4 个以太网端口。在第一个端口我有互联网。在第二个端口我有我的本地网络。当我输入“ifconfig”或“netstat -i”时，我可以在第二个接口（我的本地网络）上看到丢弃的数据包。此计数递增
em2 Link encap:Ethernet HWaddr 0c:c4:7a:7b:91:3e
inet addr:192.168.110.181 Bcast:192.168.110.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:17441 errors:0 dropped:1380 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:1226317 (1.2 MB) TX bytes:0 (0.0 B)
经过谷歌搜索，我发现了这个： https://www.novell.com/support/kb/doc.php?id=7007165
Beginning with kernel 2.6.37, it has been changed the meaning of dropped packet count. Before, dropped packets was most likely due to an error. Now, the rx_dropped counter shows statistics for dropped frames because of:
Softnet backlog full -- (Measured from /proc/net/softnet_stat)
Bad / Unintended VLAN tags
Unknown / Unregistered protocols
IPv6 frames when the server is not configured for IPv6
If any frames meet those conditions, they are dropped before the protocol stack and the rx_dropped counter is incremented.
首先，我写了这个命令：
tcpdump -vv -i em2
当我执行此命令时，第二个接口上的丢包计数停止。但是，当我中止“tcpdump”时，丢包计数再次增加。
我禁用了 IPv6，
检查了所有 VLAN。在该端口上，我在本地网络中只有一个未标记 VLAN，
我检查了文件 /proc/net/softnet_stat。在该文件中，我只有第一列的信息，这很好
00000013 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00002fbc 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
000000f3 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
0000268f 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
我用“tcpdump”分析了所有流量。我只发现了 ARP 请求、广播和 Rip。结果还不错
我启用了混杂模式，但没有帮助
我检查了电缆和连接器
我安装了最后一个驱动程序
我增加了环缓存大小，但没有帮助
我检查了所有 Unix 和 Linux：Zeroshell、Pfense、FreeBsd、Ubuntu Server（使用本机内核并由我编译）、CentOS（使用本机内核并由我编译）。全部都没有帮助
ethtool -i em2
driver: igb
version: 5.3.4.4
firmware-version: 3.25, 0x800005d0
bus-info: 0000:06:00.0
supports-statistics: yes
supports-test: yes
supports-eeprom-access: yes
supports-register-dump: yes
supports-priv-flags: no
该接口上的所有统计信息：
ethtool -S em2
NIC statistics:
rx_packets: 29675
tx_packets: 0
rx_bytes: 2208735
tx_bytes: 0
rx_broadcast: 29636
tx_broadcast: 0
rx_multicast: 39
tx_multicast: 0
multicast: 39
collisions: 0
rx_crc_errors: 0
rx_no_buffer_count: 0
rx_missed_errors: 0
tx_aborted_errors: 0
tx_carrier_errors: 0
tx_window_errors: 0
tx_abort_late_coll: 0
tx_deferred_ok: 0
tx_single_coll_ok: 0
tx_multi_coll_ok: 0
tx_timeout_count: 0
rx_long_length_errors: 0
rx_short_length_errors: 0
rx_align_errors: 0
tx_tcp_seg_good: 0
tx_tcp_seg_failed: 0
rx_flow_control_xon: 0
rx_flow_control_xoff: 0
tx_flow_control_xon: 0
tx_flow_control_xoff: 0
rx_long_byte_count: 2208735
tx_dma_out_of_sync: 0
lro_aggregated: 0
lro_flushed: 0
tx_smbus: 0
rx_smbus: 0
dropped_smbus: 0
os2bmc_rx_by_bmc: 0
os2bmc_tx_by_bmc: 0
os2bmc_tx_by_host: 0
os2bmc_rx_by_host: 0
tx_hwtstamp_timeouts: 0
rx_hwtstamp_cleared: 0
rx_errors: 0
tx_errors: 0
tx_dropped: 0
rx_length_errors: 0
rx_over_errors: 0
rx_frame_errors: 0
rx_fifo_errors: 0
tx_fifo_errors: 0
tx_heartbeat_errors: 0
tx_queue_0_packets: 0
tx_queue_0_bytes: 0
tx_queue_0_restart: 0
rx_queue_0_packets: 29675
rx_queue_0_bytes: 2090035
rx_queue_0_drops: 0
rx_queue_0_csum_err: 0
rx_queue_0_alloc_failed: 0
我哪里出错了？请帮助我。感谢您的关注。