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如何在无头服务器上为单个进程创建数据包捕获文件？

tag-icon • tag-icon wireshark packet-capture headless
如何在无头服务器上为单个进程创建数据包捕获文件？

我正在无头服务器上编写 python 脚本，我想查看该脚本的数据包捕获输出。

我无法在服务器上运行 ettercap 或 Wireshark，因为有太多其他噪音（此外，wireshark 是一个 GUI 工具）。但是我有 sudo 访问权限。

有什么方法可以只捕获该脚本生成的数据包？最好是可以加载到 Wireshark 中的格式（不是强制性的，但是，如果需要，我可以仔细阅读文本）

答案1

Wireshark 有一个命令行实用程序。我曾在只有控制台访问权限的远程计算机上使用过它，它工作得很好。只需花几分钟阅读参数即可学会如何使用它。

C:\Program Files (x86)\Wireshark>dumpcap.exe -h
Dumpcap 1.10.3 (SVN Rev 53022 from /trunk-1.10)
Capture network packets and dump them into a pcapng file.
See http://www.wireshark.org for more information.

Usage: dumpcap [options] ...

Capture interface:
  -i <interface>           name or idx of interface (def: first non-loopback),
                           or for remote capturing, use one of these formats:
                               rpcap://<host>/<interface>
                               TCP@<host>:<port>
  -f <capture filter>      packet filter in libpcap filter syntax
  -s <snaplen>             packet snapshot length (def: 65535)
  -p                       don't capture in promiscuous mode
  -B <buffer size>         size of kernel buffer in MB (def: 2MB)
  -y <link type>           link layer type (def: first appropriate)
  -D                       print list of interfaces and exit
  -L                       print list of link-layer types of iface and exit
  -d                       print generated BPF code for capture filter
  -k                       set channel on wifi interface <freq>,[<type>]
  -S                       print statistics for each interface once per second
  -M                       for -D, -L, and -S, produce machine-readable output

RPCAP options:
  -r                       don't ignore own RPCAP traffic in capture
  -u                       use UDP for RPCAP data transfer
  -A <user>:<password>     use RPCAP password authentication
  -m <sampling type>       use packet sampling
                           count:NUM - capture one packet of every NUM
                           timer:NUM - capture no more than 1 packet in NUM ms
Stop conditions:
  -c <packet count>        stop after n packets (def: infinite)
  -a <autostop cond.> ...  duration:NUM - stop after NUM seconds
                           filesize:NUM - stop this file after NUM KB
                              files:NUM - stop after NUM files
Output (files):
  -w <filename>            name of file to save (def: tempfile)
  -g                       enable group read access on the output file(s)
  -b <ringbuffer opt.> ... duration:NUM - switch to next file after NUM secs
                           filesize:NUM - switch to next file after NUM KB
                              files:NUM - ringbuffer: replace after NUM files
  -n                       use pcapng format instead of pcap (default)
  -P                       use libpcap format instead of pcapng

Miscellaneous:
  -N <packet_limit>        maximum number of packets buffered within dumpcap
  -C <byte_limit>          maximum number of bytes used for buffering packets wi
thin dumpcap
  -t                       use a separate thread per interface
  -q                       don't report packet capture counts
  -v                       print version information and exit
  -h                       display this help and exit

Example: dumpcap -i eth0 -a duration:60 -w output.pcapng
"Capture packets from interface eth0 until 60s passed into output.pcapng"

Use Ctrl-C to stop capturing at any time.

答案2

是的，您可以使用 iptables 和 dumpcap。概括：

# iptables -A OUTPUT -m owner --pid-owner 1000 -j CONNMARK --set-mark 1
# iptables -A INPUT -m connmark --mark 1 -j NFLOG --nflog-group 30 
# iptables -A OUTPUT -m connmark --mark 1 -j NFLOG --nflog-group 30 
# dumpcap -i nflog:30 -w pid-1000.pcap

这将捕获所有进程 ID 为 1000 的流量。这些命令必须在主机本身上运行（PID 信息所在的位置）。

答案3

另一种选择是通过dumpcapSSH 将输出传输到本地机器上运行的 wireshark 中。

wireshark -k -i <(ssh -l USER REMOTEHOST "dumpcap -i lo -P -w - -f 'not tcp port 22'")

这将在本地打开 wireshark 实例，显示来自远程计算机的流量。您可能希望修改过滤器，not tcp port 22以防止在网络上传输过多流量。

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