新的scapy.试图理解sr()

Question

我是scapy的新手,我正在尝试使用sr和sr1函数来理解他们的工作.

我试图制作以下数据包,我发现它已经发送了1个数据包,但它说它收到了581个数据包.有人可以帮助我理解为什么它显示了这么多收到的数据包.

收到1373个数据包,得到0个答案,剩下1个数据包

>>> p=sr(IP(dst="192.168.25.1")/TCP(dport=23))
.Begin emission:
.....Finished to send 1 packets.
...............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................^C
Received 581 packets, got 0 answers, remaining 1 packets
>>> p
(<Results: TCP:0 UDP:0 ICMP:0 Other:0>, <Unanswered: TCP:1 UDP:0 ICMP:0 Other:0>)

我的TCPDump输出没有显示它收到这么多数据包.

Answer 1

该sr()和sr1()功能会发送一个数据包,并侦听网络中的情况下,相应的答案上sr(),sr1()将等待只是一个答案.

收到但未回答的数据包是Scapy在查找对原始数据包的响应时嗅探的数据包.我不确定如何tcpdump使用Scapy同时使用Scapy会影响你的结果 - 不确定内核将数据包传递给哪个进程.

以下是来自thePacketGeek的关于使用Scapy发送和接收的优秀教程.

还要确保__doc__在解释器中使用各种Scapy函数的属性来获取相关文档.

>>> print sr1.__doc__
Send packets at layer 3 and return only the first answer
nofilter: put 1 to avoid use of bpf filters
retry:    if positive, how many times to resend unanswered packets
          if negative, how many times to retry when no more packets are answered
timeout:  how much time to wait after the last packet has been sent
verbose:  set verbosity level
multi:    whether to accept multiple answers for the same stimulus
filter:   provide a BPF filter
iface:    listen answers only on the given interface
>>>