Ubiquitous Computing Technology Research InstituteSungkyunkwan UniversitySungkyunkwan University
Using Ethereal Using Ethereal - Packet Capturing & Analysis Tool - Packet Capturing & Analysis Tool
2006. 4. 12
Sungkyunkwan University UTRI
2006710998
Park Aehui
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ContentsContents
What is Ethereal? Installing Ethereal
under Windows
Using Ethereal Tool Packet Capturing Packet Filtering Ethereal Basic Interface
Main window Filter toolbar Packet List pane Packet Detail pane Packet Byte Pane Menu
Making use of Ethereal
Reference
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What is Ethereal? (cont’d)What is Ethereal? (cont’d)
Network packet analyzer Capture network packet Display that packet as detailed as possible an open source software project / GPL(GNU General Public License)
Principal Purpose To troubleshoot network problems To examine security problems To debug protocol implementations To learn network protocol internals
Features Available for UNIX and Windows Capture live packet data from a network interface Open and Save packet data Filter packets So on..
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What is Ethereal?What is Ethereal?
Platforms Ethereal runs on Unix
Apple Mac OS X, BeOS, FreeBSD, HP-UX, IBM AIX, NetBSD, OpenBSD, SCO UnixWare/OpenUnix, SGI Irix, Sun Solaris/Intel, Sun Solaris/Sparc, Tru64 UNIX
Linux Debian GNU/Linux, Gentoo Linux, IBM S/390 Linux, Mandrake Linux, P
LD Linux, Red Hat Linux, Rock Linux, Slackware Linux, Suse Linux Microsoft Windows
Window Server 2003 / XP / 2000 / NT4.0 , Window ME / 98
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Installing Ethereal under Windows (Cont’d)Installing Ethereal under Windows (Cont’d)
Install Ethereal Download a binary installer
http://www.ethereal.com/download.html#release Since Ethereal Version 0.10.12, the WinPcap installer has become part of
the main Ethereal installer If you need, Install WinPcap
To Capture live network traffic Can go up to Application from low packet http://winpcap.polito.it Linux version - libpcap
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Installing Ethereal under WindowsInstalling Ethereal under Windows
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Packet CapturingPacket Capturing
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Packet Filtering (Cont’d)Packet Filtering (Cont’d)
How to Use Filtering Capture Options -> Capture Filter Dialog Main Toolbar
Filter Edit Box Filter Button -> Display Filter Dialog
Using the libpcap filter language for capture filter Example
Src host 10.10.10.1 ip.addr == 10.0.0.5 or http
Basic Filtering expression Logical Operations
English C-like Description
and && Logical AND ex) ip.addr==10.0.0.5 and tcp.flags.fin
or || Logical OR ex) tcp or arp
xor ^^ Logical XOR
Not ! Logical NOT ex) not tcp
[…] Substring Operator ex) ip[2:2] =92
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Packet Filtering (Cont’d)Packet Filtering (Cont’d)
Basic Filtering expression Display Filter comparison operators
Display Filter Types Unsigned integer ex) ip.len le 1500, ip.len le 0x436 Boolean ex) tcp.flag.syn Ethernet address(6byte) ex) eth.addr == ff:ff:ff:ff:ff:ff IPv4 address ex) ip.addr == 192.168.0.1 Signed integer String …
English C-like Description
eq == Equal ex) ip.addr==10.0.0.5
ne != Not equal ex) ip.addr !=10.0.0.5
gt > Greater than ex) frame.pkt_len > 10
lt < Less than ex) frame.pkt_len < 128
ge >= Greater than or equal to ex) frame.pkt_len ge 0x100
le <= Less than or equal to ex) frame.pkt_len <= 0x20
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Packet FilteringPacket Filtering
Capture Filter Example
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The Main windowThe Main window
After some packets captured or loaded
menu
main toolbar
filter toolbar
Packet detail pane
Packet Byte Pane
Statusbar
packet list pane
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Filter toolbarFilter toolbar
Quickly edit and apply display filters Filter
Bring up the filter construction dialog
Expression.. Open a dialog box that lets you edit a display
filter from a list of protocol fields
Clear Reset the current display filter and clears the
edit area
Apply Apply the current value in the edit area as the
new display filter
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The Packet List paneThe Packet List pane
Display all the packets in the current capture file Each line in the packet list corresponds to one packet default columns
No The number of the packet in the capture file
Time The timestamp of the packet ( presentation format can be changed)
Source The address where this packet is coming from
Destination The address where this packet is going to
Protocol Info
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The Packet Detail paneThe Packet Detail pane
Show the current packet (selected in the “Packet List”) in a more detailed form
Show the protocols protocol fields Display using a tree (expand / collapsed)
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The Packet Byte PaneThe Packet Byte Pane
Show the current packet (selected in the “Packet List”) in a hexdump style
Contain data picketed from multiple packets Packet Reassembling
ex) large chunks of data
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The Menu (Cont’d)The Menu (Cont’d)
File Open Open Recent Marge… Save Save As.. File Set Export
as “Plan Text” file… as “PostScript” file… as “CVS” (Comma Separated Values packet summary) file… as XML-”PSML”(packet summary) file… as XML-”PDML”(packet details) file…
Print Quit
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The Menu (Cont’d)The Menu (Cont’d)
Edit Find Packet
Find a packet by many criteria ex) source address find : ip.addr==203.252.50.24
Find Next Find Previous Time Reference Mark Packet (toggle)
Mark currently selected packet Mark All Packets Unmark All Packets Preferences…
Set preferences for many parameters User Interface – Layout / Columns / Font / Color Capture Printing Name Resolution Protocols
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The Menu (Cont’d)The Menu (Cont’d)
View Setting show or hide Setting view format
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The Menu (Cont’d)The Menu (Cont’d)
Go Back
Jump to the recently visited packet in the packet history
Forward Jump to the next visited packet in the packet history
Go to Packet specify a packet number, then go to the packet
Go to Corresponding Packet If the selected field doesn’t correspond to a packet,
the item is grey out
First Packet Jump to first packet of the capture file
Last Packet Jump to last packet of the capture file
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The Menu (Cont’d)The Menu (Cont’d)
Capture (1)
Interface Showing live captured data The interface description provided by the operation system
Open the Capture Options
The number of packets captured, Since this dialog was open
Number of packets capturedIn the last second
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The Menu (Cont’d)The Menu (Cont’d)
Capture (2) Options
select interfaceto capture
specify the maximum amount
default : 65535
file name to save
Buffer size to be usedwhile capturing
Stop capture aftern packet(s) / n megabytes /n minutes(s)
Display option while capturing
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The Menu (Cont’d)The Menu (Cont’d)
Analyze Display Filter
Bring up a dialog of display filters
Apply as Filter Change the current display filter and changed filter
immediately
Prepare a Filter Change the current display filter but won’t apply
the change filter
Enabled Protocol.. Enable/disable protocol dissectors
Decode As.. / User Specified Decodes… To decode certain packets as a particular protocol
Follow TCP Stream Expert Info Expert Info Composite
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The MenuThe Menu
Statistics Summery
Show information about the data captured
Protocol History Display a hierarchical tree of protocol statistics
Conversations Display a list of conversations (traffic between
endpoints)
Endpoint List Display a list of endpoints (traffic to/from an address)
TCP Stream Graph Round Trip Time Graph Throughput Graph
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Making use of Ethereal (Cont’d)Making use of Ethereal (Cont’d)
Analyzing web page (HTTP) packets (1) web page : http://www.skku.ac.kr (203.252.32.90:80)
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Making use of Ethereal (Cont’d)Making use of Ethereal (Cont’d)
Analyzing web page (HTTP) packets (2) Packet Summary
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Making use of EtherealMaking use of Ethereal
Analyzing web page (HTTP) packets (3) Contents
“Get” Request
“Post” Response
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Reference Reference
http://www.ethereal.com/ http://ethereal.secuwiz.com/docs/eug_html/ http://www.infoage.co.kr/newspaper/list.php http://blog.naver.com/blueysh98/100012090262