ubiquitous computing technology research institute sungkyunkwan university using ethereal - packet...

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

# 2Ubiquitous Computing Technology Research InstituteSungkyunkwan UniversitySungkyunkwan University

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


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..


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


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


Installing Ethereal under WindowsInstalling Ethereal under Windows


Packet CapturingPacket Capturing


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


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


Packet FilteringPacket Filtering

Capture Filter Example


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


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


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


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)


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


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



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



View Setting show or hide Setting view format



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



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



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



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


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


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)


Making use of Ethereal (Cont’d)Making use of Ethereal (Cont’d)

Analyzing web page (HTTP) packets (2) Packet Summary


Making use of EtherealMaking use of Ethereal

Analyzing web page (HTTP) packets (3) Contents

“Get” Request

“Post” Response


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

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