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1. Programming
Dear All,
Which is better to use ? Ascii or Pcap tracing ? Or are they complementary ? (1 Reply)
Discussion started by: knowledgeSeeker
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Hi,
I have a standard pcap file created using tcpdump. The file looks like
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06:49:36.489552 IP 192.120.148.227 > 71.126.222.64: ICMP echo request, id 512, seq 1280, length 40
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3. Programming
Hi,
i am using a linux CentOS machine. I have 2 real network interfaces
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4. Programming
Hi,
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Hi,
I am new at UNIX and programing in general and only have a basic knowledge of C++. I am helping out with some research at a college and was given the task to sort through captured packets via IP addresses. I was wondering if anyone could help me with writing a code which filters through pcap... (1 Reply)
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Can someone please help me figure out how to use pcap.h to sniff packets between only 2 computers whose mac addresses are know?
Thanks (0 Replies)
Discussion started by: papabearcares
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7. Programming
Can someone please help me figure out how to use pcap.h to sniff packets between only 2 computers whose mac addresses are know?
Thanks (0 Replies)
Discussion started by: papabearcares
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8. Programming
Hello everybody!!
I am currently doing my intership and I need some tips for Pcap.h.
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Discussion started by: danathane
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9. Programming
I cant use pcap.h include file. How can I do so? :confused: (8 Replies)
Discussion started by: Pervez Sajjad
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10. Programming
I don't know if this is the correct forum to post this but hopefully someone can atleast point me in the right direction if they can't help me.
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PCAP-SAVEFILE(5) File Formats Manual PCAP-SAVEFILE(5)
NAME
pcap-savefile - libpcap savefile format
DESCRIPTION
NOTE: applications and libraries should, if possible, use libpcap to read savefiles, rather than having their own code to read savefiles.
If, in the future, a new file format is supported by libpcap, applications and libraries using libpcap to read savefiles will be able to
read the new format of savefiles, but applications and libraries using their own code to read savefiles will have to be changed to support
the new file format.
``Savefiles'' read and written by libpcap and applications using libpcap start with a per-file header. The format of the per-file header
is:
+------------------------------+
| Magic number |
+--------------+---------------+
|Major version | Minor version |
+--------------+---------------+
| Time zone offset |
+------------------------------+
| Time stamp accuracy |
+------------------------------+
| Snapshot length |
+------------------------------+
| Link-layer header type |
+------------------------------+
All fields in the per-file header are in the byte order of the host writing the file. The first field in the per-file header is a 4-byte
magic number, with the value 0xa1b2c3d4. The magic number, when read by a host with the same byte order as the host that wrote the file,
will have the value 0xa1b2c3d4, and, when read by a host with the opposite byte order as the host that wrote the file, will have the value
0xd4c3b2a1. That allows software reading the file to determine whether the byte order of the host that wrote the file is the same as the
byte order of the host on which the file is being read, and thus whether the values in the per-file and per-packet headers need to be byte-
swapped.
Following this are:
A 2-byte file format major version number; the current version number is 2.
A 2-byte file format minor version number; the current version number is 4.
A 4-byte time zone offset; this is always 0.
A 4-byte number giving the accuracy of time stamps in the file; this is always 0.
A 4-byte number giving the "snapshot length" of the capture; packets longer than the snapshot length are truncated to the snapshot
length, so that, if the snapshot length is N, only the first N bytes of a packet longer than N bytes will be saved in the capture.
a 4-byte number giving the link-layer header type for packets in the capture; see pcap-linktype(7) for the LINKTYPE_ values that can
appear in this field.
Following the per-file header are zero or more packets; each packet begins with a per-packet header, which is immediately followed by the
raw packet data. The format of the per-packet header is:
+---------------------------------------+
| Time stamp, seconds value |
+---------------------------------------+
| Time stamp, microseconds value |
+---------------------------------------+
| Length of captured packet data |
+---------------------------------------+
|Un-truncated length of the packet data |
+---------------------------------------+
All fields in the per-packet header are in the byte order of the host writing the file. The per-packet header begins with a time stamp
giving the approximate time the packet was captured; the time stamp consists of a 4-byte value, giving the time in seconds since January 1,
1970, 00:00:00 UTC, followed by a 4-byte value, giving the time in microseconds since that second. Following that are a 4-byte value giv-
ing the number of bytes of captured data that follow the per-packet header and a 4-byte value giving the number of bytes that would have
been present had the packet not been truncated by the snapshot length. The two lengths will be equal if the number of bytes of packet data
are less than or equal to the snapshot length.
SEE ALSO
pcap(3PCAP), pcap-linktype(7)
21 October 2008 PCAP-SAVEFILE(5)