netstat -i和netstat -s平时感觉不是经常用到，有点陌生，学习一下。
netstat -i 打印网络接口信息
[root@localhost ~]# netstat -i
Kernel Interface table
Iface MTU RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR Flg
ens33 1500 2114 0 0 0 909 0 0 0 BMRU
lo 65536 0 0 0 0 0 0 0 0 LRU
Iface：网络接口名称
MTU：最大传输单元
RX-OK：接收时，正确的数据包数
RX-ERR：接收时，产生错误的数据包数
RX-DRP：接收时，丢弃的数据包数
RX-OVR：接收时，由于过速而丢失的数据包数
TX-OK：发送时，正确的数据包数
TX-ERR：发送时，产生错误的数据包数
TX-DRP：发送时，丢弃的数据包数
TX-OVR：发送时，由于过速而丢失的数据包数
Flg：标志
B 已经设置了一个广播地址
L 该接口是一个回送设备
M 接收所有的数据包(混乱模式)
N 避免跟踪
O 在该接口上，禁用ARP
P 这是一个点到点连接
R 接口正在运行
U 接口处于"活动"状态
netstat -s 按照各个协议分别显示其统计数据
[root@localhost ~]# netstat -s
Ip:
1943 total packets received
0 forwarded
0 incoming packets discarded
1103 incoming packets delivered
835 requests sent out
16 dropped because of missing route
Icmp:
1 ICMP messages received
1 input ICMP message failed.
ICMP input histogram:
echo requests: 1
6 ICMP messages sent
0 ICMP messages failed
ICMP output histogram:
destination unreachable: 6
IcmpMsg:
InType8: 1
OutType3: 6
Tcp:
1 active connections openings
1 passive connection openings
0 failed connection attempts
1 connection resets received
1 connections established
959 segments received
673 segments send out
0 segments retransmited
0 bad segments received.
0 resets sent
Udp:
143 packets received
0 packets to unknown port received.
0 packet receive errors
156 packets sent
0 receive buffer errors
0 send buffer errors
UdpLite:
TcpExt:
5 delayed acks sent
1 packets directly queued to recvmsg prequeue.
1 bytes directly received in process context from prequeue
865 packet headers predicted
24 acknowledgments not containing data payload received
41 predicted acknowledgments
TCPRcvCoalesce: 15
TCPOrigDataSent: 72
IpExt:
InNoRoutes: 3
InMcastPkts: 22
InBcastPkts: 365
InOctets: 1157801
OutOctets: 55171
InMcastOctets: 704
InBcastOctets: 51754
InNoECTPkts: 1943
