红色的比较重要。读一下这些工具的源码。

iperf：网络性能测试工具

https://iperf.fr/iperf-doc.php

-t：指定监听时间(s)

-i：指定打印间隔(s)

默认TCP窗口大小为128KB

监听30s，每隔2s打印一次。

-w ：指定TCP窗口大小

改变窗口大小看看：

-n：发送多少数据

-m： --print_mss

Tcpdump

标志中C表示cache

tcpdump过滤协议：

tcpdump中三种逻辑运算，取非运算是 'not ' '! ', 与运算是'and','&&';或运算 是'or' ,'||'；

使用and、&&

arp

ethtool

ethtool ens33：查询网口基本信息，包括速率、双工、自协商信息等。

下面这个Link detected：yes表示这个网口是接了网线的。

root@hy-virtual-machine:~# ethtool ens33
Settings for ens33:
        Supported ports: [ TP ]

        // 支持模式
        Supported link modes:   10baseT/Half 10baseT/Full 
                                100baseT/Half 100baseT/Full 
                                1000baseT/Full 
        Supported pause frame use: No
        Supports auto-negotiation: Yes // 支持自动协商
        Supported FEC modes: Not reported

        // 通告模式
        Advertised link modes:  10baseT/Half 10baseT/Full 
                                100baseT/Half 100baseT/Full 
                                1000baseT/Full 
        Advertised pause frame use: No
        Advertised auto-negotiation: Yes // 使用自动协商
        Advertised FEC modes: Not reported
        Speed: 1000Mb/s // 当前速率 1000Mb/s
        Duplex: Full // 工作模式为全双工
        Port: Twisted Pair
        PHYAD: 0
        Transceiver: internal
        Auto-negotiation: on // 自动协商打开
        MDI-X: off (auto)
        Supports Wake-on: d
        Wake-on: d
        Current message level: 0x00000007 (7)
                               drv probe link
        Link detected: yes //端口接了网线

ethtool -i ens33：查询网卡驱动信息

ethtool -d ens33：查询网路设备寄存器信息

root@hy-virtual-machine:~# ethtool -d ens33
MAC Registers
-------------
0x00000: CTRL (Device control register)  0x00C00249 //控制寄存器
      Endian mode (buffers):             little
      Link reset:                        reset
      Set link up:                       1
      Invert Loss-Of-Signal:             no
      Receive flow control:              disabled
      Transmit flow control:             disabled
      VLAN mode:                         disabled
      Auto speed detect:                 disabled
      Speed select:                      1000Mb/s
      Force speed:                       no
      Force duplex:                      no
0x00008: STATUS (Device status register) 0x0000CB83 //状态寄存器
      Duplex:                            full
      Link up:                           link config
      TBI mode:                          disabled
      Link speed:                        1000Mb/s
      Bus type:                          PCI
      Bus speed:                         66MHz
      Bus width:                         32-bit
0x00100: RCTL (Receive control register) 0x00008002 //接收控制寄存器
      Receiver:                          enabled
      Store bad packets:                 disabled
      Unicast promiscuous:               disabled
      Multicast promiscuous:             disabled
      Long packet:                       disabled
      Descriptor minimum threshold size: 1/2
      Broadcast accept mode:             accept
      VLAN filter:                       disabled
      Canonical form indicator:          disabled
      Discard pause frames:              filtered
      Pass MAC control frames:           don't pass
      Receive buffer size:               2048
0x02808: RDLEN (Receive desc length)     0x00001000
0x02810: RDH   (Receive desc head)       0x00000092
0x02818: RDT   (Receive desc tail)       0x00000090
0x02820: RDTR  (Receive delay timer)     0x00000000
0x00400: TCTL (Transmit ctrl register)   0x0103F0FA
      Transmitter:                       enabled
      Pad short packets:                 enabled
      Software XOFF Transmission:        disabled
      Re-transmit on late collision:     enabled
0x03808: TDLEN (Transmit desc length)    0x00001000
0x03810: TDH   (Transmit desc head)      0x00000027
0x03818: TDT   (Transmit desc tail)      0x00000027
0x03820: TIDV  (Transmit delay timer)    0x00000008
PHY type:                                M88
M88 PHY STATUS REGISTER:                 0x0000AC00
      Jabber:                            no
      Polarity:                          normal
      Downshifted:                       no
      MDI/MDIX:                          MDI
      Cable Length Estimate:             0-50 meters
      Link State:                        Up
      Speed & Duplex Resolved:           Yes
      Page Received:                     No
      Duplex:                            Full
      Speed:                             1000 mbps
M88 PHY CONTROL REGISTER:                0x00000B68
      Jabber function:                   enabled
      Auto-polarity:                     disabled
      SQE Test:                          disabled
      CLK125:                            enabled
      Auto-MDIX:                         auto
      Extended 10Base-T Distance:        disabled
      100Base-TX Interface:              5-bit
      Scrambler:                         disabled
      Force Link Good:                   disabled
      Assert CRS on Transmit:            enabled

ethtool - S ens33：查询网口收发包统计信息

root@hy-virtual-machine:~# ethtool -S ens33
NIC statistics:
     rx_packets: 348285
     tx_packets: 167633
     rx_bytes: 295334312
     tx_bytes: 29736337
     rx_broadcast: 0
     tx_broadcast: 0
     rx_multicast: 0
     tx_multicast: 0
     rx_errors: 0
     tx_errors: 0
     tx_dropped: 0
     multicast: 0
     collisions: 0
     rx_length_errors: 0
     rx_over_errors: 0
     rx_crc_errors: 0
     rx_frame_errors: 0
     rx_no_buffer_count: 0
     rx_missed_errors: 0
     tx_aborted_errors: 0
     tx_carrier_errors: 0
     tx_fifo_errors: 0
     tx_heartbeat_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
     tx_restart_queue: 0
     rx_long_length_errors: 0
     rx_short_length_errors: 0
     rx_align_errors: 0
     tx_tcp_seg_good: 1390
     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: 295334312
     rx_csum_offload_good: 261684
     rx_csum_offload_errors: 1
     alloc_rx_buff_failed: 0
     tx_smbus: 0
     rx_smbus: 0
     dropped_smbus: 0

ethtool -s ens33 autoneg off speed 100 duplex full ：设置网口工作速率、双工、自协商

root@hy-virtual-machine:~# ethtool -s ens33 autoneg off speed 100 duplex full  
root@hy-virtual-machine:~# ethtool ens33
Settings for ens33:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full 
                                100baseT/Half 100baseT/Full 
                                1000baseT/Full 
        Supported pause frame use: No
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  Not reported
        Advertised pause frame use: No
        Advertised auto-negotiation: No
        Advertised FEC modes: Not reported
        Speed: 100Mb/s
        Duplex: Full
        Port: Twisted Pair
        PHYAD: 0
        Transceiver: internal
        Auto-negotiation: off
        MDI-X: off (auto)
        Supports Wake-on: d
        Wake-on: d
        Current message level: 0x00000007 (7)
                               drv probe link
        Link detected: yes

ip命令

ip -s link ls ens33：查看端口收发包信息

root@hy-virtual-machine:~# ip -s link ls ens33
2: ens33:  mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
    link/ether 00:0c:29:59:dd:f5 brd ff:ff:ff:ff:ff:ff
    RX: bytes  packets  errors  dropped overrun mcast   
    294140472  351070   0       16228   0       0       
    TX: bytes  packets  errors  dropped carrier collsns 
    29853978   168800   0       0       0       0   

ip link show：查看端口二层信息

root@hy-virtual-machine:~# ip link show
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: ens33:  mtu 1500 qdisc fq_codel state UP mode DEFAULT group default qlen 1000
    link/ether 00:0c:29:59:dd:f5 brd ff:ff:ff:ff:ff:ff

ip addr show：查看端口二三层信息

root@hy-virtual-machine:~# ip addr show
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33:  mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:59:dd:f5 brd ff:ff:ff:ff:ff:ff
    inet 192.168.1.6/24 brd 192.168.1.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet6 2409:8a4d:c52:60e0:d04:f582:6766:6078/64 scope global temporary dynamic 
       valid_lft 258924sec preferred_lft 82304sec
    inet6 2409:8a4d:c52:60e0:9cb5:72a9:1d3f:a4d3/64 scope global dynamic mngtmpaddr noprefixroute 
       valid_lft 258924sec preferred_lft 172524sec
    inet6 fe80::cfbd:7121:57cc:56f4/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

nmap：重要

root@hy-virtual-machine:~# nmap -v localhost
Starting Nmap 7.80 ( https://nmap.org ) at 2020-06-01 21:27 CST
Initiating SYN Stealth Scan at 21:27
Scanning localhost (127.0.0.1) [1000 ports]
Discovered open port 139/tcp on 127.0.0.1
Discovered open port 22/tcp on 127.0.0.1
Discovered open port 445/tcp on 127.0.0.1
Discovered open port 631/tcp on 127.0.0.1
Completed SYN Stealth Scan at 21:27, 0.08s elapsed (1000 total ports)
Nmap scan report for localhost (127.0.0.1)
Host is up (0.0000090s latency).
Not shown: 996 closed ports
PORT    STATE SERVICE
22/tcp  open  ssh
139/tcp open  netbios-ssn
445/tcp open  microsoft-ds
631/tcp open  ipp

Read data files from: /usr/bin/../share/nmap
Nmap done: 1 IP address (1 host up) scanned in 0.15 seconds
           Raw packets sent: 1000 (44.000KB) | Rcvd: 2004 (84.176KB)

nslookup：

域名解析

root@hy-virtual-machine:~# nslookup www.baidu.com
Server:         127.0.0.53
Address:        127.0.0.53#53

Non-authoritative answer:
www.baidu.com   canonical name = www.a.shifen.com.
Name:   www.a.shifen.com
Address: 36.152.44.96
Name:   www.a.shifen.com
Address: 36.152.44.95
Name:   www.a.shifen.com
Address: ::1