Note that the filesize is limited to a maximum value of 2 GiB. In "multiple files" mode, Dumpcap will write to several capture files. When the first capture file fills up, Dumpcap will switch writing to the next file and so on. The created filenames are based on the filename given with the -w option, the number of the file and on the creation date and time, e.
With the files option it's also possible to form a "ring buffer". This will fill up new files until the number of files specified, at which point Dumpcap will discard the data in the first file and start writing to that file and so on.
If the files option is not set, new files filled up until one of the capture stop conditions match or until the disk is full. The criterion is of the form key:value, where key is one of: duration:value switch to the next file after value seconds have elapsed, even if the current file is not completely filled up.
This value must be less than Caution should be used when using large numbers of files: some filesystems do not handle many files in a single directory well. The files criterion requires either duration or filesize to be specified to control when to go to the next file.
It should be noted that each -b parameter takes exactly one criterion; to specify two criterion, each must be preceded by the -b option. Example: -b filesize -b files:5 results in a ring buffer of five files of size one megabyte each. This is used by the capture driver to buffer packet data until that data can be written to disk. If you encounter packet drops while capturing, try to increase this size. Note that, while Dumpcap attempts to set the buffer size to 2 MiB by default, and can be told to set it to a larger value, the system or interface on which you're capturing might silently limit the capture buffer size to a lower value or raise it to a higher value.
This is available on UNIX systems with libpcap 1. It is not available on UNIX systems with earlier versions of libpcap. This option can occur multiple times. If used before the first occurrence of the -i option, it sets the default capture buffer size.
If used after an -i option, it sets the capture buffer size for the interface specified by the last -i option occurring before this option. If the capture buffer size is not set specifically, the default capture buffer size is used instead.
If used in combination with the -N option, both limits will apply. Setting this limit will enable the usage of the separate thread per interface. For each network interface, a number and an interface name, possibly followed by a text description of the interface, is printed.
The interface name or the number can be supplied to the -i option to specify an interface on which to capture. This can be useful on systems that don't have a command to list them e. The files criterion requires either duration or filesize to be specified to control when to go to the next file. It should be noted that each -b parameter takes exactly one criterion; to specify two criterion, each must be preceded by the -b option.
Example: -b filesize -b files:5 results in a ring buffer of five files of size one megabyte each. This is available on UNIX systems with libpcap 1. It is not available on UNIX systems with earlier versions of libpcap.
This option can occur multiple times. If used before the first occurrence of the -i option, it sets the default capture buffer size. If used after an -i option, it sets the capture buffer size for the interface specified by the last -i option occurring before this option. If the capture buffer size is not set specifically, the default capture buffer size is used instead. This can be useful on systems that don't have a command to list them e. Depending on your system you may need to run dumpcap from an account with special privileges for example, as root to be able to capture network traffic.
If " dumpcap -D " is not run from such an account, it will not list any interfaces. The entire filter expression must be specified as a single argument which means that if it contains spaces, it must be quoted.
If used before the first occurrence of the -i option, it sets the default capture filter expression. If used after an -i option, it sets the capture filter expression for the interface specified by the last -i option occurring before this option.
If the capture filter expression is not set specifically, the default capture filter expression is used if provided. If no interface is specified, Dumpcap searches the list of interfaces, choosing the first non-loopback interface if there are any non-loopback interfaces, and choosing the first loopback interface if there are no non-loopback interfaces.
If there are no interfaces at all, Dumpcap reports an error and doesn't start the capture. Data read from pipes must be in standard pcap format. When capturing from multiple interfaces, the capture file will be saved in pcap-ng format. Note that in monitor mode the adapter might disassociate from the network with which it's associated, so that you will not be able to use any wireless networks with that adapter. This could prevent accessing files on a network server, or resolving host names or network addresses, if you are capturing in monitor mode and are not connected to another network with another adapter.
This could prevent accessing files on a network server, or resolving host names or network addresses, if you are capturing in monitor mode and are not connected to another network with another adapter. If used before the first occurrence of the -i option, it enables the monitor mode for all interfaces. If used after an -i option, it enables the monitor mode for the interface specified by the last -i option occurring before this option. Set the channel on the interface; this is supported only on IEEE The values for type are.
List the data link types supported by the interface and exit. The reported link types can be used for the -y option. When used with -D , -L , -S or --list-time-stamp-types print machine-readable output. The machine-readable output is intended to be read by Wireshark and TShark ; its format is subject to change from release to release. Limit the number of packets used for storing captured packets in memory while processing it.
If used in combination with the -C option, both limits will apply. Note that the interface might be in promiscuous mode for some other reason; hence, -p cannot be used to ensure that the only traffic that is captured is traffic sent to or from the machine on which Dumpcap is running, broadcast traffic, and multicast traffic to addresses received by that machine.
If used before the first occurrence of the -i option, no interface will be put into the promiscuous mode. If used after an -i option, the interface specified by the last -i option occurring before this option will not be put into the promiscuous mode. Save files as pcap instead of the default pcapng. In situations that require pcapng, such as capturing from multiple interfaces, this option will be overridden. Set the default snapshot length to use when capturing live data. No more than snaplen bytes of each network packet will be read into memory, or saved to disk.
A value of 0 specifies a snapshot length of , so that the full packet is captured; this is the default. If used before the first occurrence of the -i option, it sets the default snapshot length. If used after an -i option, it sets the snapshot length for the interface specified by the last -i option occurring before this option. If the snapshot length is not set specifically, the default snapshot length is used if provided.
Set the data link type to use while capturing packets. The values reported by -L are the values that can be used. If used before the first occurrence of the -i option, it sets the default capture link type.
If used after an -i option, it sets the capture link type for the interface specified by the last -i option occurring before this option. If the capture link type is not set specifically, the default capture link type is used if provided. This option may be specified multiple times. Note that Wireshark currently only displays the first comment of a capture file. List time stamp types supported for the interface. If no time stamp type can be set, no time stamp types are listed.
This is the manual page for Dumpcap 3. Dumpcap is part of the Wireshark distribution. Dumpcap is derived from the Wireshark capturing engine code; see the list of authors in the Wireshark man page for a list of authors of that code. The criterion is of the form key:value , where key is one of:. Dump the code generated for the capture filter in a human-readable form, and exit.
0コメント