// WSUG Chapter IO

[#ChapterIO]

== File Input, Output, And Printing

[#ChIOIntroductionSection]

=== Introduction

This chapter will describe input and output of capture data.

* Open capture files in various capture file formats

* Save and export capture files in various formats

* Merge capture files together

* Import text files containing hex dumps of packets

* Print packets

[#ChIOOpenSection]

=== Open Capture Files

Wireshark can read in previously saved capture files. To read them, simply
select the menu:File[Open] menu or toolbar item. Wireshark will then pop up
the “File Open” dialog box, which is discussed in more detail in <<ChIOOpen>>.

[TIP]
.You can use drag and drop to open files
====
On most systems you can open a file by simply dragging it in your file manager and dropping it onto Wireshark’s main window.
====

If you haven’t previously saved the current capture file you will be asked to
do so to prevent data loss. This warning can be disabled in the preferences.

In addition to its native file format (pcapng), Wireshark can read and write
capture files from a large number of other packet capture programs as well. See
<<ChIOInputFormatsSection>> for the list of capture formats Wireshark
understands.

[#ChIOOpen]

==== The “Open Capture File” Dialog Box

The “Open Capture File” dialog box allows you to search for a capture file
containing previously captured packets for display in Wireshark. The following
sections show some examples of the Wireshark “Open File” dialog box. The
appearance of this dialog depends on the system. However, the functionality
should be the same across systems.

Common dialog behavior on all systems:

* Select files and directories.

* Click the btn:[Open] button to accept your selected file and open it.

* Click the btn:[Cancel] button to go back to Wireshark and not load a capture file.

* The btn:[Help] button will take you to this section of the “User’s Guide”.

Wireshark adds the following controls:

* View file preview information such as the size and the number of packets in a selected a capture file.

// XXX - we need a better description of these read filters
* Specify a read filter with the “Read filter” field.
  This filter will be used when opening the new file.
  The text field background will turn green for a valid filter string and red for an invalid one.
  Read filters can be used to exclude various types of traffic, which can be useful for large capture files.
  They use the same syntax as display filters, which are discussed in detail in <<ChWorkDisplayFilterSection>>.

* Optionally force Wireshark to read a file as a particular type using the “Automatically detect file type” drop-down.

[#ChIOOpenFileDialogWin32]

.“Open” on Microsoft Windows
image::images/ws-open-win32.png[{medium-screenshot-attrs}]

This is the common Windows file open dialog along with some Wireshark extensions.

[#ChIOOpenFileDialog]

.“Open” - Linux and UNIX
image::images/ws-open-qt5.png[{medium-screenshot-attrs}]

This is the common Qt file open dialog along with some Wireshark extensions.

// XXX Add macOS

[#ChIOInputFormatsSection]


==== Input File Formats

The native capture file formats used by Wireshark are:

* pcap. The default format used by the _libpcap_ packet capture library. Used
  by _tcpdump, _Snort_, _Nmap_, _Ntop_, and many other tools.

* pcapng.  A flexible, extensible successor to the pcap format.
  Wireshark 1.8 and later save files as pcapng by default.  Versions
  prior to 1.8 used pcap.  Used by Wireshark and by _tcpdump_ in newer
  versions of macOS.

The following file formats from other capture tools can be opened by Wireshark:

* Oracle (previously Sun) _snoop_ and _atmsnoop_ captures

* Finisar (previously Shomiti) _Surveyor_ captures

* Microsoft _Network Monitor_ captures

* Novell _LANalyzer_ captures

* AIX _iptrace_ captures

* Cinco Networks NetXray captures

* NETSCOUT (previously Network Associates/Network General) Windows-based
  Sniffer and Sniffer Pro captures

* Network General/Network Associates DOS-based Sniffer captures
  (compressed or uncompressed) captures

* LiveAction (previously WildPackets/Savvius)
  *Peek/EtherHelp/PacketGrabber captures

* RADCOM’s WAN/LAN Analyzer captures

* Viavi (previously Network Instruments) Observer captures

* Lucent/Ascend router debug output

* captures from HP-UX nettl

* Toshiba’s ISDN routers dump output

* output from _i4btrace_ from the ISDN4BSD project

* traces from the EyeSDN USB S0

* the IPLog format output from the Cisco Secure Intrusion Detection System

* pppd logs (pppdump format)

* the output from VMS’s TCPIPtrace/TCPtrace/UCX$TRACE utilities

* the text output from the DBS Etherwatch VMS utility

* Visual Networks’ Visual UpTime traffic capture

* the output from CoSine L2 debug

* the output from InfoVista (previously Accellent) 5Views LAN agents

* Endace Measurement Systems’ ERF format captures

* Linux Bluez Bluetooth stack hcidump -w traces

* Catapult (now Ixia/Keysight) DCT2000 .out files

* Gammu generated text output from Nokia DCT3 phones in Netmonitor mode

* IBM Series (OS/400) Comm traces (ASCII &amp; UNICODE)

* Juniper Netscreen snoop captures

* Symbian OS btsnoop captures

* Tamosoft CommView captures

* Tektronix K12xx 32bit .rf5 format captures

* Tektronix K12 text file format captures

* Apple PacketLogger captures

* Captures from Aethra Telecommunications’ PC108 software for their test instruments

* Citrix NetScaler Trace files

* Android Logcat binary and text format logs

* Colasoft Capsa and PacketBuilder captures

* Micropross mplog files

* Unigraf DPA-400 DisplayPort AUX channel monitor traces

* 802.15.4 traces from Daintree's Sensor Network Analyzer

* MPEG-2 Transport Streams as defined in ISO/IEC 13818-1

* Log files from the _candump_ utility

* Logs from the BUSMASTER tool

* Ixia IxVeriWave raw captures

* Rabbit Labs CAM Inspector files

* _systemd_ journal files

* 3GPP TS 32.423 trace files

New file formats are added from time to time.

It may not be possible to read some formats dependent on the packet types
captured. Ethernet captures are usually supported for most file formats but it
may not be possible to read other packet types such as PPP or IEEE 802.11 from
all file formats.

[#ChIOSaveSection]

=== Saving Captured Packets

You can save captured packets by using the menu:File[Save] or menu:File[Save As...] menu items.
You can choose which packets to save and which file format to be used.

Not all information will be saved in a capture file. For example, most file
formats don’t record the number of dropped packets. See
<<ChAppFilesCaptureFilesSection>> for details.

[#ChIOSaveAs]

==== The “Save Capture File As” Dialog Box

The “Save Capture File As” dialog box allows you to save the current capture to a file.
The exact appearance of this dialog depends on your system.
However, the functionality is the same across systems.
Examples are shown below.

[#ChIOSaveAsFileWin32]

.“Save” on Microsoft Windows
image::images/ws-save-as-win32.png[{medium-screenshot-attrs}]

This is the common Windows file save dialog with some additional Wireshark extensions.

[#ChIOSaveAsFile2]

.“Save” on Linux and UNIX
image::images/ws-save-as-qt5.png[{medium-screenshot-attrs}]

This is the common Qt file save dialog with additional Wireshark extensions.

// XXX Add macOS

You can perform the following actions:

* Type in the name of the file in which you wish to save the captured packets.

* Select the directory to save the file into.

* Specify the format of the saved capture file by clicking on the “Save as” drop-down box.
  You can choose from the types described in <<ChIOOutputFormatsSection>>.
  Some capture formats may not be available depending on the packet types captured.

* The btn:[Help] button will take you to this section of the “User’s Guide”.

* “Compress with gzip” will compress the capture file as it is being written to disk.

* Click the btn:[Save] button to accept your selected file and save it.

* Click on the btn:[Cancel] button to go back to Wireshark without saving any packets.

If you don’t provide a file extension to the filename (e.g., `.pcap`) Wireshark will append the standard file extension for that file format.

[TIP]
.Wireshark can convert file formats
====
You can convert capture files from one format to another by opening a capture and saving it as a different format.
====

If you wish to save some of the packets in your capture file you can do so via <<ChIOExportSpecifiedPacketsDialog>>.

[#ChIOOutputFormatsSection]

==== Output File Formats

Wireshark can save the packet data in its native file format (pcapng) and in the
file formats of other protocol analyzers so other tools can read the capture
data.

[NOTE]
.Saving in a different format might lose data
====
Saving your file in a different format might lose information such as comments, name resolution, and time stamp resolution.
See <<ChAdvTimestamps>> for more information on time stamps.
====

The following file formats can be saved by Wireshark (with the known file extensions):

* pcapng ({asterisk}.pcapng). A flexible, extensible successor to the
  libpcap format. Wireshark 1.8 and later save files as pcapng by
  default. Versions prior to 1.8 used libpcap.

* pcap ({asterisk}.pcap).  The default format used by the _libpcap_
  packet capture library.  Used by _tcpdump, _Snort_, _Nmap_, _Ntop_,
  and many other tools.

* Accellent 5Views ({asterisk}.5vw)

* captures from HP-UX nettl ({asterisktrc0,{asterisk}.trc1)

* Microsoft Network Monitor - NetMon ({asterisk}.cap)

* Network Associates Sniffer - DOS
  ({asterisk}.cap,{asterisk}.enc,{asterisk}.trc,{asterisk}.fdc,{asterisk}.syc)

* Cinco Networks NetXray captures ({asterisk}.cap)

* Network Associates Sniffer - Windows ({asterisk}.cap)

* Network Instruments/Viavi Observer ({asterisk}.bfr)

* Novell LANalyzer ({asterisk}.tr1)

* Oracle (previously Sun) snoop ({asterisk}.snoop,{asterisk}.cap)

* Visual Networks Visual UpTime traffic ({asterisk}.{asterisk})

* Symbian OS btsnoop captures ({asterisk}.log)

* Tamosoft CommView captures ({asterisk}.ncf)

* Catapult (now Ixia/Keysight) DCT2000 .out files ({asterisk}.out)

* Endace Measurement Systems’ ERF format capture({asterisk}.erf)

* EyeSDN USB S0 traces ({asterisk}.trc)

* Tektronix K12 text file format captures ({asterisk}.txt)

* Tektronix K12xx 32bit .rf5 format captures ({asterisk}.rf5)

* Android Logcat binary logs ({asterisk}.logcat)

* Android Logcat text logs ({asterisk}.{asterisk})

* Citrix NetScaler Trace files ({asterisk}.cap)

New file formats are added from time to time.

Whether or not the above tools will be more helpful than Wireshark is a different question ;-)

[NOTE]
.Third party protocol analyzers may require specific file extensions
====
Wireshark examines a file’s contents to determine its type. Some other protocol
analyzers only look at a file's extension. For example, you might need to use
the `.cap` extension in order to open a file using the Windows version
of _Sniffer_.
====

[#ChIOMergeSection]

=== Merging Capture Files

Sometimes you need to merge several capture files into one. For example, this can
be useful if you have captured simultaneously from multiple interfaces at once
(e.g., using multiple instances of Wireshark).

There are three ways to merge capture files using Wireshark:

* Use the menu:File[Merge] menu to open the “Merge” dialog.
  See <<ChIOMergeDialog>> for details.
  This menu item will be disabled unless you have loaded a capture file.

* Use _drag and drop_ to drop multiple files on the main window.
  Wireshark will try to merge the packets in chronological order from the dropped files into a newly created temporary file.
  If you drop a single file, it will simply replace the existing capture.

* Use the `mergecap` tool from the command line to merge capture files.
  This tool provides the most options to merge capture files.
  See <<AppToolsmergecap>> for details.

[#ChIOMergeDialog]

==== The “Merge With Capture File” Dialog Box

This lets you select a file to be merged into the currently loaded file.
If your current data has not been saved you will be asked to save it first.

Most controls of this dialog will work the same way as described in the “Open Capture File” dialog box.
See <<ChIOOpen>> for details.

Specific controls of this merge dialog are:

Prepend packets::
Prepend the packets from the selected file before the currently loaded packets.

Merge chronologically::
Merge both the packets from the selected and currently loaded file in chronological order.

Append packets::
Append the packets from the selected file after the currently loaded packets.

[#ChIOMergeFileTab]

.“Merge Capture File As” dialog box examples

[#ChIOMergeFileWin32]

.“Merge” on Microsoft Windows
image::images/ws-merge-win32.png[{medium-screenshot-attrs}]

This is the common Windows file open dialog with additional Wireshark extensions.

[#ChIOMergeFile2]

.“Merge” on Linux and UNIX
image::images/ws-merge-qt5.png[{medium-screenshot-attrs}]

This is the Qt file open dialog with additional Wireshark extensions.

// XXX Add macOS

[#ChIOImportSection]

=== Import Hex Dump

Wireshark can read in a hex dump and write the data described into a
temporary libpcap capture file. It can read hex dumps with multiple packets in
them, and build a capture file of multiple packets. It is also capable of
generating dummy Ethernet, IP and UDP, TCP, or SCTP headers, in order to build
fully processable packet dumps from hexdumps of application-level data only.
Alternatively, a Dummy PDU header can be added to specify a dissector the data
should be passed to initially.

Two methods for converting the input are supported:

==== Standard ASCII Hexdumps

Wireshark understands a hexdump of the form generated by `od -Ax -tx1 -v`.
In other words, each byte is individually displayed, with spaces separating
the bytes from each other.  Hex digits can be upper or lowercase.

In normal operation, each line must begin with an offset describing the
position in the packet, followed a colon, space, or tab separating it from
the bytes.  There is no limit on the width or number of bytes per line, but
lines with only hex bytes without a leading offset are ignored (i.e.,
line breaks should not be inserted in long lines that wrap.) Offsets are more
than two digits; they are in hex by default, but can also be in octal or
decimal.  Each packet must begin with offset zero, and an offset
zero indicates the beginning of a new packet.  Offset values must be correct;
an unexpected value causes the current packet to be aborted and the next
packet start awaited.  There is also a single packet mode with no offsets.

Packets may be preceded by a direction indicator ('I' or 'O') and/or a
timestamp if indicated.  If both are present, the direction indicator precedes
the timestamp.  The format of the timestamps must be specified.  If no timestamp
is parsed, in the case of the first packet the current system time is used,
while subsequent packets are written with timestamps one microsecond later than
that of the previous packet.

Other text in the input data is ignored. Any text before the offset is
ignored, including email forwarding characters '>'. Any text on a line
after the bytes is ignored, e.g., an ASCII character dump (but see *-a* to
ensure that hex digits in the character dump are ignored).  Any line where
the first non-whitespace character is a '#' will be ignored as a comment.
Any lines of text between the bytestring lines are considered preamble;
the beginning of the preamble is scanned for the direction indicator and
timestamp as mentioned above and otherwise ignored.

Any line beginning with #TEXT2PCAP is a directive and options
can be inserted after this command to be processed by Wireshark.
Currently there are no directives implemented; in the future, these may
be used to give more fine-grained control on the dump and the way it
should be processed e.g., timestamps, encapsulation type etc.

In general, short of these restrictions, Wireshark is pretty liberal
about reading in hexdumps and has been tested with a variety of
mangled outputs (including being forwarded through email multiple
times, with limited line wrap etc.)

Here is a sample dump that can be imported, including optional
directional indicator and timestamp:

----
I 2019-05-14T19:04:57Z
000000 00 e0 1e a7 05 6f 00 10 ........
000008 5a a0 b9 12 08 00 46 00 ........
000010 03 68 00 00 00 00 0a 2e ........
000018 ee 33 0f 19 08 7f 0f 19 ........
000020 03 80 94 04 00 00 10 01 ........
000028 16 a2 0a 00 03 50 00 0c ........
000030 01 01 0f 19 03 80 11 01 ........
----

==== Regular Text Dumps

Wireshark is also capable of scanning the input using a custom Perl regular
expression as specified by GLib's https://developer-old.gnome.org/glib/stable/glib-regex-syntax.html[GRegex here].
Using a regex capturing a single packet in the given file
Wireshark will search the given file from start to the second to last character
(the last character has to be `\n` and is ignored)
for non-overlapping (and non-empty) strings matching the given regex and then
identify the fields to import using named capturing subgroups. Using provided
format information for each field they are then decoded and translated into a
standard libpcap file retaining packet order.

Note that each named capturing subgroup has to match _exactly_ once a packet,
but they may be present multiple times in the regex.

For example, the following dump:
----
> 0:00:00.265620 a130368b000000080060
> 0:00:00.280836 a1216c8b00000000000089086b0b82020407
< 0:00:00.295459 a2010800000000000000000800000000
> 0:00:00.296982 a1303c8b00000008007088286b0bc1ffcbf0f9ff
> 0:00:00.305644 a121718b0000000000008ba86a0b8008
< 0:00:00.319061 a2010900000000000000001000600000
> 0:00:00.330937 a130428b00000008007589186b0bb9ffd9f0fdfa3eb4295e99f3aaffd2f005
> 0:00:00.356037 a121788b0000000000008a18
----
could be imported using these settings:
----
regex: ^(?<dir>[<>])\s(?<time>\d+:\d\d:\d\d.\d+)\s(?<data>[0-9a-fA-F]+)$
timestamp: %H:%M:%S.%f
dir: in: <   out: >
encoding: HEX
----

Caution has to be applied when discarding the anchors `^` and `$`, as the input
is searched, not parsed, meaning even most incorrect regexes will produce valid
looking results when not anchored (however, anchors are not guaranteed to prevent
this). It is generally recommended to sanity check any files created using
this conversion.

Supported fields:

* data: Actual captured frame data
+
The only mandatory field. This should match the encoded binary data captured and
is used as the actual frame data to import.
+
* time: timestamp for the packet
+
The captured field will be parsed according to the given timestamp format into a
timestamp.
+
If no timestamp is present an arbitrary counter will count up seconds and
nanoseconds by one each packet.

* dir: the direction the packet was sent over the wire
+
The captured field is expected to be one character in length, any remaining
characters are ignored (e.g., given "Input" only the 'I' is looked at). This
character is compared to lists of characters corresponding to inbound and
outbound and the packet is assigned the corresponding direction.
If neither list yields a match, the direction is set to unknown.
+
If this field is not specified the entire file has no directional information.
+
* seqno: an ID for this packet
+
Each packet can be assigned an arbitrary ID that can used as field by Wireshark.
This field is assumed to be a positive integer base 10. This field can e.g.
be used to reorder out of order captures after the import.
+
If this field is not given, no IDs will be present in the resulting file.
+

[#ChIOImportDialog]


==== The “Import From Hex Dump” Dialog Box

This dialog box lets you select a text file, containing a hex dump of packet
data, to be imported and set import parameters.

[#ChIOFileImportDialog]

.The “Import from Hex Dump” dialog in Hex Dump mode
image::images/ws-file-import.png[{medium-screenshot-attrs}]

Specific controls of this import dialog are split in three sections:

File Source:: Determine which input file has to be imported

Input Format:: Determine how the input file has to be interpreted.

Encapsulation:: Determine how the data is to be encapsulated.

==== File source

Filename / Browse::
Enter the name of the text file to import. You can use _Browse_ to browse for a
file.

==== Input Format

This section is split in the two alternatives for input conversion, accessible in
the two Tabs "Hex Dump" and "Regular Expression"

In addition to the conversion mode specific inputs, there are also common
parameters, currently only the timestamp format.

===== The Hex Dump tab

Offsets::
Select the radix of the offsets given in the text file to import. This is
usually hexadecimal, but decimal and octal are also supported. Select _None_
when only the bytes are present. These will be imported as a single packet.

Direction indication::
Tick this box if the text file to import has direction indicators before each
frame. These are on a separate line before each frame and start with either
_I_ or _i_ for input and _O_ or _o_ for output.

===== The Regular Expression tab

.The "Regular Expression" tab inside the "Import from Hex Dump” dialog.
image::images/ws-file-import-regex.png[{medium-screenshot-attrs}]

Packet format regular expression::
This is the regex used for searching packets and metadata inside the input file.
Named capturing subgroups are used to find the individual fields. Anchors `^` and
`$` are set to match directly before and after newlines `\n` or `\r\n`. See
https://developer-old.gnome.org/glib/stable/glib-regex-syntax.html[GRegex] for a full
documentation.

Data encoding::
The Encoding used for the binary data. Supported encodings are plain-hexadecimal,
-octal, -binary and base64. Plain here means no additional
characters are present in the data field beyond whitespaces, which are ignored.
Any unexpected characters abort the import process.
+
Ignored whitespaces are `\r`, `\n`, `\t`, `\v`, ` ` and only for hex `:`, only
for base64 `=`.
+
Any incomplete bytes at the field's end are assumed to be padding to fill the
last complete byte. These bits should be zero, however, this is not checked.

Direction indication::
The lists of characters indicating incoming vs. outgoing packets. These fields
are only available when the regex contains a `(?<dir>...)` group.

===== Common items

Timestamp Format::
This is the format specifier used to parse the timestamps in the text file to
import. It uses the same format as `strptime(3)` with the addition of `%f` for
zero padded fractions of seconds. The precision of `%f` is determined from its
length. The most common fields are `%H`, `%M` and `%S` for hours, minutes and
seconds. The straightforward HH:MM:SS format is covered by %T. For a full
definition of the syntax look for `strptime(3)`,
+
In Regex mode this field is only available when a `(?<time>...)` group is present.
+
In Hex Dump mode if there are no timestamps in the text file to import, leave this
field empty and timestamps will be generated based on the time of import.

==== Encapsulation

Encapsulation type::
Here you can select which type of frames you are importing. This all depends on
from what type of medium the dump to import was taken. It lists all types that
Wireshark understands, so as to pass the capture file contents to the right
dissector.

Dummy header::
When Ethernet encapsulation is selected you have to option to prepend dummy
headers to the frames to import. These headers can provide artificial Ethernet,
IP, UDP, TCP or SCTP headers or SCTP data chunks. When selecting a type of
dummy header, the applicable entries are enabled, others are greyed out and
default values are used.
When the _Wireshark Upper PDU export_ encapsulation is selected the option
_ExportPDU_ becomes available. This allows you to select the name of the
dissector these frames are to be directed to.

Maximum frame length::
You may not be interested in the full frames from the text file, just the first
part. Here you can define how much data from the start of the frame you want to
import. If you leave this open the maximum is set to 256kiB.

Once all input and import parameters are setup click btn:[Import] to start the
import. If your current data wasn’t saved before you will be asked to save it
first.

If the import button doesn't unlock, make sure all encapsulation parameters are
in the expected range and all unlocked fields are populated when using regex mode
(the placeholder text is not used as default).

When completed there will be a new capture file loaded with the frames imported
from the text file.

[#ChIOFileSetSection]

=== File Sets

When using the “Multiple Files” option while doing a capture (see:
<<ChCapCaptureFiles>>), the capture data is spread over several capture files,
called a file set.

As it can become tedious to work with a file set by hand, Wireshark provides
some features to handle these file sets in a convenient way.

.How does Wireshark detect the files of a file set?
****
A filename in a file set uses the format Prefix_Number_DateTimeSuffix which
might look something like `test_00001_20240714183910.pcap`. All files of a file
set share the same prefix (e.g., “test”) and suffix (e.g., “.pcap”) and a
varying middle part.

To find the files of a file set, Wireshark scans the directory where the
currently loaded file resides and checks for files matching the filename pattern
(prefix and suffix) of the currently loaded file.

This simple mechanism usually works well but has its drawbacks. If several file
sets were captured with the same prefix and suffix, Wireshark will detect them
as a single file set. If files were renamed or spread over several directories
the mechanism will fail to find all files of a set.
****

The following features in the menu:File[File Set] submenu are available to work
with file sets in a convenient way:

*  The “List Files” dialog box will list the files Wireshark has recognized as
   being part of the current file set.

*  btn:[Next File] closes the current and opens the next file in the file
   set.

*  btn:[Previous File] closes the current and opens the previous file in the
   file set.

[#ChIOFileSetListDialog]

==== The “List Files” Dialog Box

.The “List Files” dialog box
image::images/ws-file-set-dialog.png[{medium-screenshot-attrs}]

Each line contains information about a file of the file set:

Filename::
The name of the file. If you click on the filename (or the radio
button left to it), the current file will be closed and the corresponding
capture file will be opened.

Created::
The creation time of the file.

Last Modified::
The last time the file was modified.

Size::
The size of the file.

The last line will contain info about the currently used directory where all of
the files in the file set can be found.

The content of this dialog box is updated each time a capture file is
opened/closed.

The btn:[Close] button will, well, close the dialog box.

[#ChIOExportSection]

// - Add {missing} for other exports?

=== Exporting Data

Wireshark provides a variety of options for exporting packet data.
This section describes general ways to export data from the main Wireshark application.
There are many other ways to export or extract data from capture files, including processing <<AppToolstshark,tshark>> output and customizing Wireshark and TShark using Lua scripts.

[#ChIOExportSpecifiedPacketsDialog]

==== The “Export Specified Packets” Dialog Box

.The “Export Specified Packets” dialog box
image::images/ws-export-specified-packets.png[{medium-screenshot-attrs}]

This is similar to the “<<ChIOSaveAs,Save>>” dialog box, but it lets you save specific packets.
This can be useful for trimming irrelevant or unwanted packets from a capture file.
See <<ChIOPacketRangeSection,Packet Range>> for details on the range controls.

[#ChIOExportPacketDissectionsDialog]

==== The “Export Packet Dissections” Dialog Box

This lets you save the packet list, packet details, and packet bytes as plain text, CSV, JSON, and other formats.

.The “Export Packet Dissections” dialog box
image::images/ws-export-packet-dissections.png[{medium-screenshot-attrs}]

The format can be selected from the “Export As” drop-down and further customized using the “<<ChIOPacketRangeSection,Packet Range>>” and “<<ChIOPacketRangeSection,Packet Format>>” controls.
Some controls are unavailable for some formats, notably CSV and JSON.
The following formats are supported:

* Plain text as shown in the main window
* link:{wikipedia-main-url}Comma-separated_values[Comma-separated values (CSV)]
* link:{wikipedia-main-url}C_(programming_language)[C-compatible] byte arrays
* link:https://web.archive.org/web/20141115200425/http://www.nbee.org/doku.php?id=netpdl:psml_specification[PSML] (summary XML)
* link:https://web.archive.org/web/20140416072301/http://www.nbee.org/doku.php?id=netpdl:pdml_specification[PDML] (detailed XML)
* link:{wikipedia-main-url}JSON[JavaScript Object Notation (JSON)]

Here are some examples of exported data:

.Plain text
----
No.     Time           Source                Destination           Protocol Length SSID       Info
      1 0.000000       200.121.1.131         172.16.0.122          TCP      1454              10554 → 80 [ACK] Seq=1 Ack=1 Win=65535 Len=1400 [TCP segment of a reassembled PDU]

Frame 1: 1454 bytes on wire (11632 bits), 1454 bytes captured (11632 bits)
Ethernet II, Src: 00:50:56:c0:00:01, Dst: 00:0c:29:42:12:13
Internet Protocol Version 4, Src: 200.121.1.131 (200.121.1.131), Dst: 172.16.0.122 (172.16.0.122)
    0100 .... = Version: 4
    .... 0101 = Header Length: 20 bytes (5)
    Differentiated Services Field: 0x00 (DSCP: CS0, ECN: Not-ECT)
    Total Length: 1440
    Identification: 0x0141 (321)
    Flags: 0x0000
    ...0 0000 0000 0000 = Fragment offset: 0
    Time to live: 106
    Protocol: TCP (6)
    Header checksum: 0xd390 [validation disabled]
    [Header checksum status: Unverified]
    Source: 200.121.1.131 (200.121.1.131)
    Destination: 172.16.0.122 (172.16.0.122)
    [Source GeoIP: PE, ASN 6147, Telefonica del Peru S.A.A.]
Transmission Control Protocol, Src Port: 10554, Dst Port: 80, Seq: 1, Ack: 1, Len: 1400
----


[TIP]
====
If you would like to be able to <<ChIOImportSection,import>> any previously exported packets from a plain text file it is recommended that you do the following:

*  Add the “Absolute date and time” column.

*  Temporarily hide all other columns.

*  Disable the menu:Edit[Preferences,Protocols,Data] “Show not dissected data
   on new Packet Bytes pane” preference. More details are provided in
   <<ChCustPreferencesSection>>

*  Include the packet summary line.

*  Exclude column headings.

*  Exclude packet details.

*  Include the packet bytes.
====

.CSV
----
"No.","Time","Source","Destination","Protocol","Length","SSID","Info","Win Size"
"1","0.000000","200.121.1.131","172.16.0.122","TCP","1454","","10554  >  80 [ACK] Seq=1 Ack=1 Win=65535 Len=1400 [TCP segment of a reassembled PDU]","65535"
"2","0.000011","172.16.0.122","200.121.1.131","TCP","54","","[TCP ACKed unseen segment] 80  >  10554 [ACK] Seq=1 Ack=11201 Win=53200 Len=0","53200"
"3","0.025738","200.121.1.131","172.16.0.122","TCP","1454","","[TCP Spurious Retransmission] 10554  >  80 [ACK] Seq=1401 Ack=1 Win=65535 Len=1400 [TCP segment of a reassembled PDU]","65535"
"4","0.025749","172.16.0.122","200.121.1.131","TCP","54","","[TCP Window Update] [TCP ACKed unseen segment] 80  >  10554 [ACK] Seq=1 Ack=11201 Win=63000 Len=0","63000"
"5","0.076967","200.121.1.131","172.16.0.122","TCP","1454","","[TCP Previous segment not captured] [TCP Spurious Retransmission] 10554  >  80 [ACK] Seq=4201 Ack=1 Win=65535 Len=1400 [TCP segment of a reassembled PDU]","65535"
----

.JSON
----
{
    "_index": "packets-2014-06-22",
    "_type": "doc",
    "_score": null,
    "_source": {
      "layers": {
        "frame": {
          "frame.encap_type": "1",
          "frame.time": "Jun 22, 2014 13:29:41.834477000 PDT",
          "frame.offset_shift": "0.000000000",
          "frame.time_epoch": "1403468981.834477000",
          "frame.time_delta": "0.450535000",
          "frame.time_delta_displayed": "0.450535000",
          "frame.time_relative": "0.450535000",
          "frame.number": "2",
          "frame.len": "86",
          "frame.cap_len": "86",
          "frame.marked": "0",
          "frame.ignored": "0",
          "frame.protocols": "eth:ethertype:ipv6:icmpv6",
          "frame.coloring_rule.name": "ICMP",
          "frame.coloring_rule.string": "icmp || icmpv6"
        },
        "eth": {
          "eth.dst": "33:33:ff:9e:e3:8e",
          "eth.dst_tree": {
            "eth.dst_resolved": "33:33:ff:9e:e3:8e",
            "eth.dst.oui": "3355647",
            "eth.addr": "33:33:ff:9e:e3:8e",
            "eth.addr_resolved": "33:33:ff:9e:e3:8e",
            "eth.addr.oui": "3355647",
            "eth.dst.lg": "1",
            "eth.lg": "1",
            "eth.dst.ig": "1",
            "eth.ig": "1"
          },
          "eth.src": "00:01:5c:62:8c:46",
          "eth.src_tree": {
            "eth.src_resolved": "00:01:5c:62:8c:46",
            "eth.src.oui": "348",
            "eth.src.oui_resolved": "Cadant Inc.",
            "eth.addr": "00:01:5c:62:8c:46",
            "eth.addr_resolved": "00:01:5c:62:8c:46",
            "eth.addr.oui": "348",
            "eth.addr.oui_resolved": "Cadant Inc.",
            "eth.src.lg": "0",
            "eth.lg": "0",
            "eth.src.ig": "0",
            "eth.ig": "0"
          },
          "eth.type": "0x000086dd"
        },
        "ipv6": {
          "ipv6.version": "6",
          "ip.version": "6",
          "ipv6.tclass": "0x00000000",
          "ipv6.tclass_tree": {
            "ipv6.tclass.dscp": "0",
            "ipv6.tclass.ecn": "0"
          },
          "ipv6.flow": "0x00000000",
          "ipv6.plen": "32",
          "ipv6.nxt": "58",
          "ipv6.hlim": "255",
          "ipv6.src": "2001:558:4080:16::1",
          "ipv6.addr": "2001:558:4080:16::1",
          "ipv6.src_host": "2001:558:4080:16::1",
          "ipv6.host": "2001:558:4080:16::1",
          "ipv6.dst": "ff02::1:ff9e:e38e",
          "ipv6.addr": "ff02::1:ff9e:e38e",
          "ipv6.dst_host": "ff02::1:ff9e:e38e",
          "ipv6.host": "ff02::1:ff9e:e38e",
          "ipv6.geoip.src_summary": "US, ASN 7922, Comcast Cable Communications, LLC",
          "ipv6.geoip.src_summary_tree": {
            "ipv6.geoip.src_country": "United States",
            "ipv6.geoip.country": "United States",
            "ipv6.geoip.src_country_iso": "US",
            "ipv6.geoip.country_iso": "US",
            "ipv6.geoip.src_asnum": "7922",
            "ipv6.geoip.asnum": "7922",
            "ipv6.geoip.src_org": "Comcast Cable Communications, LLC",
            "ipv6.geoip.org": "Comcast Cable Communications, LLC",
            "ipv6.geoip.src_lat": "37.751",
            "ipv6.geoip.lat": "37.751",
            "ipv6.geoip.src_lon": "-97.822",
            "ipv6.geoip.lon": "-97.822"
          }
        },
        "icmpv6": {
          "icmpv6.type": "135",
          "icmpv6.code": "0",
          "icmpv6.checksum": "0x00005b84",
          "icmpv6.checksum.status": "1",
          "icmpv6.reserved": "00:00:00:00",
          "icmpv6.nd.ns.target_address": "2001:558:4080:16:be36:e4ff:fe9e:e38e",
          "icmpv6.opt": {
            "icmpv6.opt.type": "1",
            "icmpv6.opt.length": "1",
            "icmpv6.opt.linkaddr": "00:01:5c:62:8c:46",
            "icmpv6.opt.src_linkaddr": "00:01:5c:62:8c:46"
          }
        }
      }
    }
  }
]
----

[#ChIOExportSelectedDialog]

==== The “Export Selected Packet Bytes” Dialog Box

Export the bytes selected in the “Packet Bytes” pane into a raw binary file.

.The “Export Selected Packet Bytes” dialog box
image::images/ws-export-selected.png[{medium-screenshot-attrs}]

File name::
The file name to export the packet data to.

Save as type::
The file extension.

[#ChIOExportPDUSDialog]

==== The “Export PDUs to File...” Dialog Box

The “Export PDUs to File...” dialog box allows you to filter the captured Protocol Data Units (PDUs) and export them into the file. It allows you to export reassembled PDUs avoiding lower layers such as HTTP without TCP, and decrypted PDUs without the lower protocols such as HTTP without TLS and TCP.

. In the main menu select menu:File[Export PDUs to File...]. Wireshark will open a corresponding dialog <<ExportPDUsToFile>>.
+
[#ExportPDUsToFile]
+
.Export PDUs to File window
image::images/ws-export-pdus-to-file.png[{screenshot-attrs}]

. To select the data according to your needs, optionally type a filter value into the `Display Filter` field. For more information about filter syntax, see the link:https://www.wireshark.org/docs/man-pages/wireshark-filter.html[Wireshark Filters] man page.

. In the field below the `Display Filter` field you can choose the level from which you want to export the PDUs to the file. There are seven levels:
+
.. `DLT User`. You can export a protocol, which is framed in the user data link type table without the need to reconfigure the DLT user table. For more information, see the link:https://gitlab.com/wireshark/wireshark/-/wikis/HowToDissectAnything[How to Dissect Anything] page.
+
.. `DVB-CI`. You can use it for the Digital Video Broadcasting (DVB) protocol.
+
.. `Logcat` and `Logcat Text`. You can use them for the Android logs.
+
.. `OSI layer 3`. You can use it to export PDUs encapsulated in the IPSec or SCTP protocols.
+
.. `OSI layer 4`. You can use it to export PDUs encapsulated in the TCP or UDP protocols.
+
.. `OSI layer 7`. You can use it to export the following protocols: CredSSP over TLS, Diameter, protocols encapsulated in TLS and DTLS, H.248, Megaco, RELOAD framing, SIP, SMPP.
+
NOTE: As a developer you can add any dissector to the existing list or define a new entry in the list by using the functions in `epan/exported_pdu.h`.

. To finish exporting PDUs to file, click the btn:[OK] button in the bottom-right corner. This will close the originally captured file and open the exported results instead as a temporary file in the main Wireshark window.

. You may save the temporary file just like any captured file. See <<ChIOSaveSection>> for details.
+
NOTE: The file produced has a `Wireshark Upper PDU` encapsulation type that has somewhat limited support outside of Wireshark, but is very flexible and can contain PDUs for any protocol for which there is a Wireshark dissector.

[#ChIOStripHeaders]

==== The “Strip Headers...” Dialog Box

The “Strip Headers...” dialog box allows you to filter known encapsulation types on whatever protocol layer they appear and export them into a new capture file, removing lower-level protocols. It allows you to export reassembled packets and frames without lower layers such as GPF, GRE, GSE, GTP-U, MPLS, MPE, PPP, and more. If Wireshark has performed decryption, then you can export decrypted IP from protocols like IEEE 802.11 or IPSec without having to save encryption keys.

The procedure is similar to that of <<ChIOExportPDUSDialog>>:

. In the main menu select menu:File[Strip Headers...]. Wireshark will open a corresponding dialog.

. To select the data according to your needs, optionally type a filter value into the `Display Filter` field. For more information about filter syntax, see the link:https://www.wireshark.org/docs/man-pages/wireshark-filter.html[Wireshark Filters] man page.

. In the field below the `Display Filter` field you can choose the encapsulation type you want to find and export to the file. There are two encapsulations supported:
+
.. `Ethernet`. You can use it to export Ethernet encapsulated in other protocols.
+
.. `IP`. You can use it to export IPv4 and IPv6 encapsulated in other protocols.
+
NOTE: As a developer you can add encapsulations to the list by using the functions in `epan/exported_pdu.h`.

. To finish exporting to file, click the btn:[OK] button in the bottom-right corner. This will close the originally captured file and open the exported results instead as a temporary file in the main Wireshark window.

. You may save the temporary file just like any captured file. See <<ChIOSaveSection>> for details.
+
NOTE: The new capture files produced have standard encapsulation types and can be read in nearly any tool.

[#ChIOExportTLSSessionKeys]

==== The “Export TLS Session Keys...” Dialog Box

Transport Layer Security (TLS) encrypts the communication between a client and a server. The most common use for it is web browsing via HTTPS.

Decryption of TLS traffic requires TLS secrets. You can get them in the form of stored session keys in a "key log file", or by using an RSA private key file. For more details, see the link:{wireshark-wiki-url}TLS[TLS wiki page].

The menu:File[Export TLS Session Keys…] menu option generates a new "key log file" which contains TLS session secrets known by Wireshark. This feature is useful if you typically decrypt TLS sessions using the RSA private key file. The RSA private key is very sensitive because it can be used to decrypt other TLS sessions and impersonate the server. Session keys can be used only to decrypt sessions from the packet capture file. However, session keys are the preferred mechanism for sharing data over the Internet.

To export captured TLS session keys, follow the steps below:

. In the main menu select menu:File[Export TLS Session Keys...]. Wireshark will open a corresponding dialog <<TlsSessionKeys>>.
+
[#TlsSessionKeys]
+
.Export TLS Session Keys window
image::images/ws-tls-session-keys.png[{screenshot-attrs}]

. Type the desired file name in the `Save As` field.

. Choose the destination folder for your file in the `Where` field.

. Press the btn:[Save] button to complete the export file procedure.

[#ChIOExportObjectsDialog]

==== The “Export Objects” Dialog Box

This feature scans through the selected protocol's streams in the currently
open capture file or running capture and allows the user to export reassembled
objects to the disk. For example, if you select HTTP, you can export HTML
documents, images, executables, and any other files transferred over HTTP
to the disk. If you have a capture running, this list is automatically
updated every few seconds with any new objects seen. The saved objects can then
be opened or examined independently of Wireshark.

.The “Export Objects” dialog box
image::images/ws-export-objects.png[{screenshot-attrs}]

Columns:

Packet::
The packet number in which this object was found. In some
cases, there can be multiple objects in the same packet.

Hostname::
The hostname of the server that sent this object.

Content Type::
The content type of this object.

Size::
The size of this object in bytes.

Filename:
The filename for this object. Each protocol generates
the filename differently. For example, HTTP uses the
final part of the URI and IMF uses the subject of the email.

Inputs:

Text Filter::
Only displays objects containing the specified text string.

Help::
Opens this section of the “User’s Guide”.

Save All::
Saves all objects (including those not displayed) using the filename from the
filename column. You will be asked what directory or folder to save them in.

Close::
Closes the dialog without exporting.

Save::
Saves the currently selected object as a filename you specify. The
default filename to save as is taken from the filename column of the objects
list.

[#ChIOPrintSection]

=== Printing Packets

To print packets, select the menu:File[Print...] menu item.
Wireshark will display the “Print” dialog box as shown below.

[WARNING]
.It’s easy to waste paper doing this
====
Printed output can contain lots of text, particularly if you print packet details and bytes.
====

==== The “Print” Dialog Box

[#ChIOPrintDialogBox]

.The “Print” dialog box
image::images/ws-print.png[{medium-screenshot-attrs}]

The “Print” dialog box shows a preview area which shows the result of changing the packet format settings.
You can zoom in and out using the kbd:[{plus}] and kbd:[-] keys and reset the zoom level using the kbd:[0] key.
The following settings are available in the Print dialog box:

Packet Format::
Lets you specify what gets printed. See <<ChIOPacketFormatFrame>> for details.

Summary line:::
Include a summary line for each packet.
The line will contain the same fields as the packet list.

Details:::
Print details for each packet.

Bytes:::
Print a hex dump of each packet.

Packet Range::
Select the packets to be printed. See <<ChIOPacketRangeSection>> for details.

btn:[Page Setup...] lets you select the page size and orientation.

btn:[Print...] prints to your default printer.

btn:[Cancel] will close the dialog without printing.

btn:[Help] will display this section of the “User’s Guide”.

[#ChIOPacketRangeSection]

=== The “Packet Range” Frame

The packet range frame is a part of the “<<ChIOExportSpecifiedPacketsDialog,Export Specified Packets>>,” “<<ChIOExportPacketDissectionsDialog,Export Packet Dissections>>,” and “<<ChIOPrintSection,Print>>” dialog boxes.
You can use it to specify which packets will be exported or printed.

[#ChIOPacketRangeFrame]

.The “Packet Range” frame
image::images/ws-packet-range.png[{medium-screenshot-attrs}]

By default, the btn:[Displayed] button is set, which only exports or prints the packets that match the current display filter.
Selecting btn:[Captured] will export or print all packets.
You can further limit what you export or print to the following:

All packets::
All captured or displayed packets depending on the primary selection above.

Selected packet::
Only the selected packet.

Marked packets::
Only marked packets. See <<ChWorkMarkPacketSection>>.

First to last marked::
Lets you mark an inclusive range of packets.

Range::
Lets you manually specify a range of packets, e.g., _5,10-15,20-_ will process the packet number five, the packets from packet number ten to fifteen (inclusive) and every packet from number twenty to the end of the capture.

Remove ignored packets::
Don't export or print ignored packets.
See <<ChWorkIgnorePacketSection>>.

[#ChIOPacketFormatSection]

=== The Packet Format Frame

The packet format frame is also a part of the “<<ChIOExportPacketDissectionsDialog,Export Packet Dissections>>” and “<<ChIOPrintSection,Print>>” dialog boxes.
You can use it to specify which parts of dissection are exported or printed.

[#ChIOPacketFormatFrame]

.The “Packet Format” frame
image::images/ws-packet-format.png[{small-screenshot-attrs}]

Each of the settings below correspond to the packet list, packet detail, and packet bytes in the main window.

Packet summary line::
Export or print each summary line as shown in the “Packet List” pane.

Packet details::
Export or print the contents of the “Packet Details” tree.

All collapsed:::
Export or print as if the “Packet Details” tree is in the “all collapsed” state.

As displayed:::
Export or print as if the “Packet Details” tree is in the “as displayed” state.

All expanded:::
Export or print as if the “Packet Details” tree is in the “all expanded” state.

Packet Bytes::
Export or print the contents of the “Packet Bytes” pane.

Each packet on a new page::
For printing and some export formats, put each packet on a separate page.
For example, when exporting to a text file this will put a form feed character between each packet.

Capture information header::
Add a header to each page with capture filename and the number of total packets and shown packets.

// End of WSUG Chapter IO
