Ubiquitous Computing Technology Research Institute Sungkyunkwan University Using Ethereal - Packet Capturing & Analysis Tool Sungkyunkwan University UTRI Park Aehui

# 2 Ubiquitous Computing Technology Research Institute Sungkyunkwan University Contents  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

# 3 Ubiquitous Computing Technology Research Institute Sungkyunkwan University 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..

# 4 Ubiquitous Computing Technology Research Institute Sungkyunkwan University 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, PLD Linux, Red Hat Linux, Rock Linux, Slackware Linux, Suse Linux  Microsoft Windows Window Server 2003 / XP / 2000 / NT4.0, Window ME / 98

# 5 Ubiquitous Computing Technology Research Institute Sungkyunkwan University Installing Ethereal under Windows (Cont’d)  Install Ethereal  Download a binary installer Since Ethereal Version , 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 Linux version - libpcap

# 6 Ubiquitous Computing Technology Research Institute Sungkyunkwan University Installing Ethereal under Windows

# 7 Ubiquitous Computing Technology Research Institute Sungkyunkwan University Packet Capturing

# 8 Ubiquitous Computing Technology Research Institute Sungkyunkwan University 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 ip.addr == or http  Basic Filtering expression  Logical Operations EnglishC-likeDescription and&&Logical AND ex) ip.addr== 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

# 9 Ubiquitous Computing Technology Research Institute Sungkyunkwan University 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 == Signed integer String … EnglishC-likeDescription eq==Equal ex) ip.addr== ne!=Not equal ex) ip.addr != 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

# 10 Ubiquitous Computing Technology Research Institute Sungkyunkwan University Packet Filtering  Capture Filter Example

# 11 Ubiquitous Computing Technology Research Institute Sungkyunkwan University The Main window  After some packets captured or loaded menu main toolbar filter toolbar Packet detail pane Packet Byte Pane Statusbar packet list pane

# 12 Ubiquitous Computing Technology Research Institute Sungkyunkwan University Filter 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

# 13 Ubiquitous Computing Technology Research Institute Sungkyunkwan University The 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

# 14 Ubiquitous Computing Technology Research Institute Sungkyunkwan University The 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)

# 15 Ubiquitous Computing Technology Research Institute Sungkyunkwan University The 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

# 16 Ubiquitous Computing Technology Research Institute Sungkyunkwan University 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

# 17 Ubiquitous Computing Technology Research Institute Sungkyunkwan University The Menu (Cont’d)  Edit  Find Packet Find a packet by many criteria ex) source address find : ip.addr==  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

# 18 Ubiquitous Computing Technology Research Institute Sungkyunkwan University The Menu (Cont’d)  View  Setting show or hide  Setting view format

# 19 Ubiquitous Computing Technology Research Institute Sungkyunkwan University 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

# 20 Ubiquitous Computing Technology Research Institute Sungkyunkwan University 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 captured In the last second

# 21 Ubiquitous Computing Technology Research Institute Sungkyunkwan University The Menu (Cont’d)  Capture (2)  Options select interface to capture specify the maximum amount default : file name to save Buffer size to be used while capturing Stop capture after n packet(s) / n megabytes / n minutes(s) Display option while capturing

# 22 Ubiquitous Computing Technology Research Institute Sungkyunkwan University 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

# 23 Ubiquitous Computing Technology Research Institute Sungkyunkwan University The 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

# 24 Ubiquitous Computing Technology Research Institute Sungkyunkwan University Making use of Ethereal (Cont’d)  Analyzing web page (HTTP) packets (1)  web page : ( :80)

# 25 Ubiquitous Computing Technology Research Institute Sungkyunkwan University Making use of Ethereal (Cont’d)  Analyzing web page (HTTP) packets (2)  Packet Summary

# 26 Ubiquitous Computing Technology Research Institute Sungkyunkwan University Making use of Ethereal  Analyzing web page (HTTP) packets (3)  Contents “Get” Request “Post” Response

# 27 Ubiquitous Computing Technology Research Institute Sungkyunkwan University Reference    