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成品免费观看网站,网络货运怎么做的,wordpress免费还是收费,怎样选择网站的关键词目录 目录 前言 tcpdump命令的常见参数 “-h”#xff1a;查看帮助信息 “--version”#xff1a;查看版本号 “-D”#xff1a;列出系统中所有可以用于tcpdump抓取数据包的网卡列表 “-i”#xff1a;指定哪个网卡接口 “host”#xff1a;筛选出指定的主机IP的相…目录目录前言tcpdump命令的常见参数“-h”查看帮助信息“--version”查看版本号“-D”列出系统中所有可以用于tcpdump抓取数据包的网卡列表“-i”指定哪个网卡接口“host”筛选出指定的主机IP的相关数据包“port”指定哪个端口例如“-w”把包数据直接写入指定的文件中而不进行分析和打印输出tcpdump抓包文件的解析总结前言tcpdump是强大的网络数据采集分析工具之一称为抓包工具。它可以将网络中传送的数据包完全截获下来提供分析。它支持针对网络层、协议、主机、网络或端口的过滤并提供逻辑语句来帮助我们过滤掉无用的信息。其中tcpdump字面拆分tcp传输控制协议transmission control protocol位于传输层dump导出的意思。tcpdump命令的常见参数“-h”查看帮助信息例如# tcpdump -h tcpdump version 4.9.3 libpcap version 1.9.1 (with TPACKET_V3) Usage: tcpdump [-aAbdDefhHIJKlLnNOpqStuUvxX#] [ -B size ] [ -c count ] [ -C file_size ] [ -E algo:secret ] [ -F file ] [ -G seconds ] [ -i interface ] [ -j tstamptype ] [ -M secret ] [ --number ] [ -Q in|out|inout ] [ -r file ] [ -s snaplen ] [ --time-stamp-precision precision ] [ --immediate-mode ] [ -T type ] [ --version ] [ -V file ] [ -w file ] [ -W filecount ] [ -y datalinktype ] [ -z postrotate-command ] [ -Z user ] [ expression ]“--version”查看版本号例如# tcpdump --version tcpdump version 4.9.3 libpcap version 1.9.1 (with TPACKET_V3)“-D”列出系统中所有可以用于tcpdump抓取数据包的网卡列表例如# tcpdump -D 1.wlan0 [Up, Running] 2.any (Pseudo-device that captures on all interfaces) [Up, Running] 3.lo [Loopback]“-i”指定哪个网卡接口例如# tcpdump -i wlan0 tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on wlan0, link-type EN10MB (Ethernet), capture size 262144 bytes 00:22:21.386610 IP 192.168.169.59.38394 192.168.32.3.domain: 5 SRV? _sips._tcp.sipgz04.hbq.r.10086.cn. (51) ... 00:22:21.560149 IP 192.168.169.59.7879 180.76.76.76.domain: 42514 AAAA? gap.work.weixin.qq.com. (40) 00:22:21.562346 IP 192.168.169.59.20975 180.76.76.76.domain: 17325 A? gap.work.weixin.qq.com. (40)“host”筛选出指定的主机IP的相关数据包例如# tcpdump host 192.168.169.1 tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on wlan0, link-type EN10MB (Ethernet), capture size 262144 bytes 18:20:50.598341 IP 192.168.169.59.39338 192.168.169.1.www: Flags [S], seq 2224882238, win 65535, options [mss 1460,sackOK,TS val 1395385504 ecr 0,nop,wscale 9], length 0 18:20:50.598450 IP 192.168.169.1.www 192.168.169.59.39338: Flags [S.], seq 4160180220, ack 2224882239, win 65160, options [mss 1460,sackOK,TS val 2182696542 ecr 1395385504,nop,wscale 3], length 0 18:20:50.603623 IP 192.168.169.59.39338 192.168.169.1.www: Flags [.], ack 1, win 128, options [nop,nop,TS val 1395385527 ecr 2182696542], length 0 18:20:50.603965 IP 192.168.169.59.39338 192.168.169.1.www: Flags [P.], seq 1:212, ack 1, win 128, options [nop,nop,TS val 1395385528 ecr 2182696542], length 211: HTTP: GET /app/getparamvalue?paramrec HTTP/1.1 18:20:50.604034 IP 192.168.169.1.www 192.168.169.59.39338: Flags [.], ack 212, win 8119, options [nop,nop,TS val 2182696547 ecr 1395385528], length 0 ...“port”指定哪个端口例如# tcpdump port 554 tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on wlan0, link-type EN10MB (Ethernet), capture size 262144 bytes 18:36:22.460633 IP 192.168.169.1.554 192.168.169.59.41456: Flags [P.], seq 1908680467:1908680662, ack 3404164144, win 8010, options [nop,nop,TS val 2183627926 ecr 1396316862], length 195: RTSP 18:36:22.484299 IP 192.168.169.59.41456 192.168.169.1.554: Flags [.], ack 195, win 1532, options [nop,nop,TS val 1396316913 ecr 2183627926], length 0 18:36:22.491079 IP 192.168.169.1.554 192.168.169.59.41456: Flags [P.], seq 195:470, ack 1, win 8010, options [nop,nop,TS val 2183627957 ecr 1396316913], length 275: RTSP 18:36:22.495765 IP 192.168.169.59.41456 192.168.169.1.554: Flags [.], ack 470, win 1532, options [nop,nop,TS val 1396316943 ecr 2183627957], length 0 18:36:22.531393 IP 192.168.169.1.554 192.168.169.59.41456: Flags [P.], seq 470:759, ack 1, win 8010, options [nop,nop,TS val 2183627997 ecr 1396316943], length 289: RTSP 18:36:22.538752 IP 192.168.169.59.41456 192.168.169.1.554: Flags [.], ack 759, win 1532, options [nop,nop,TS val 1396316985 ecr 2183627997], length 0 18:36:22.571757 IP 192.168.169.1.554 192.168.169.59.41456: Flags [P.], seq 759:1014, ack 1, win 8010, options [nop,nop,TS val 2183628038 ecr 1396316985], length 255: RTSP 18:36:22.578728 IP 192.168.169.59.41456 192.168.169.1.554: Flags [.], ack 1014, win 1532, options [nop,nop,TS val 1396317025 ecr 2183628038], length 0 18:36:22.606963 IP 192.168.169.1.554 192.168.169.59.41456: Flags [P.], seq 1014:1309, ack 1, win 8010, options [nop,nop,TS val 2183628073 ecr 1396317025], length 295: RTSP ...“-w”把包数据直接写入指定的文件中而不进行分析和打印输出注意这里的文件后缀名为pcap或cap。例如# tcpdump -w /mnt/card/test.pcap tcpdump: listening on wlan0, link-type EN10MB (Ethernet), capture size 262144 bytestcpdump抓包文件的解析pcap或cap文件是常见的数据报存储格式文件数据按照特定格式存储普通编辑器无法正常打开该类型的文件或无法直观查看数据的重要信息。它们需要特定的解析工具软件才能直观地读取并查看如wireshark等。总结tcpdump是一款命令行网络数据包捕获和分析工具主要用于实时监控和诊断网络流量。‌‌核心作用‌ tcpdump的核心功能是捕获流经指定网络接口的数据包并基于网络层协议、主机地址、端口号或数据包方向等条件进行过滤分析。它通过Berkeley Packet FilterBPF语法高效筛选数据输出格式包含时间戳、源/目标IP及端口等信息便于快速识别异常流量或协议交互。‌‌适用场景‌ tcpdump广泛应用于以下领域‌网络故障排查‌通过捕获数据包定位连接超时、路由问题或服务不可达等故障例如分析TCP三次握手过程。‌性能监控与流量分析‌统计特定主机或端口的流量模式评估带宽利用率识别网络瓶颈。‌安全监控与威胁检测‌捕获可疑流量如异常端口访问或扫描行为辅助入侵检测。‌协议分析与开发调试‌验证自定义协议行为或调试网络应用通信细节。