Justniffer Just A Network TCP Packet Sniffer .Justniffer is a network protocol analyzer that captures network traffic and produces logs in a customized way, can emulate Apache web server log files, track response times and extract all "intercepted" files from the HTTP traffic

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Network TCP Packet Sniffer

Justniffer is a network protocol analyzer that captures network traffic and produces logs in a customized way, can emulate Apache web server log files, track response times and extract all “intercepted” files from the HTTP traffic.

It lets you interactively trace tcp traffic from a live network or from a previously saved capture file. Justniffer’s native capture file format is libpcap format, which is also the format used by tcpdump and various other tools.

Reliable TCP Flow Rebuilding

The main Justniffer’s feature is the ability to handle all those complex low level protocol issues and retrieve the correct flow of the TCP/IP traffic: IP fragmentation, TCP retransmission, reordering. etc. It uses portions of Linux kernel source code for handling all TCP/IP stuff. Precisely, it uses a slightly modified version of the libnids libraries that already include a modified version of Linux code in a more reusable way.

Optimized for “Request / Response” protocols. It is able to track server response time

Justniffer was born as tool for helping in analyzing performance problem in complex network environment when it becomes impractical to analyze network captures solely using wireshark. It will help you to quickly identify the most significant bottlenecks analyzing the performance at “application” protocol level.

In very complex and distributed systems is often useful to understand how communication takes place between different components, and when this is implemented as a network protocol based on TCP/IP (HTTP, JDBC, RTSP, SIP, SMTP, IMAP, POP, LDAP, REST, XML-RPC, IIOP, SOAP, etc.), justniffer becomes very useful. Often the logging level and monitoring systems of these systems does not report important information to determine performance issues such as the response time of each network request. Because they are in a “production” environment and cannot be too much verbose or they are in-house developed applications and do not provide such logging.

Other times it is desirable to collect access logs from web services implemented on different environments (various web servers, application servers, python web frameworks, etc.) or web services that are not accessible and therefore traceable only on client side.

Justniffer can capture traffic in promiscuous mode so it can be installed on dedicated and independent station within the same network “collision domain” of the gateway of the systems that must be analyzed, collecting all traffic without affecting the system performances and requiring invasive installation of new software in production environments.

Can rebuild and save HTTP content on files

The robust implementation for the reconstruction of the TCP flow turns it in a multipurpose sniffer.

HTTP sniffer LDAP sniffer SMTP sniffer SIP sniffer password sniffer justniffer can also be used to retrieve files sent over the network.

It is extensible

Can be extended by external scripts. A python script has been developed to recover all files sent via HTTP (images, text, html, javascript, etc.).

Features Summary


The main feature of justniffer is to analize network traffic to monitor performances. The performances related keywords are: %connection.time %idle.time.0 %request.time %response.time %response.time.begin %response.time.end %idle.time.1

+---------+                           +---------+

|         |                           |         |

|  Client |                           | Server  |

|         |                           |         |

+---------+                           +---------+

    |                                     |

    |  -----   connect syn   -------->    |----+

    |                                     |    |

    |  <------   syn/ack    --------->    |    | %connection.time

    |                                     |    |

    |  -------     ack     ---------->    |    |

    |           ESTABLISHED               |----+

    |                                     |    | %idle.time.0 

    |                                     |    |(after connection, before 

    |                                     |    | request)

    |                                     |    |

    |  ---  request/first packet  --->    |----+

    |  <------     ack     -----------    |    |

    |                                     |    |

    |  ---  request/....          --->    |    | %request.time

    |  <------     ack     -----------    |    |

    |                                     |    |

    |  ---   request/last packet  --->    |    |

    |  <------     ack     -----------    |----+--------------------+

    |                                     |    |                    |

    |                                     |    |                    |

    |                                     |    |%response.time.begin |   

    |                                     |    |                    |

    |  <--  response/first packet ----    |----+                    | response 

    |  -------     ack     ---------->    |    |                    | time

    |                                     |    |                    |

    |  <--  response/....         ----    |    |%response.time.end   |

    |  -------     ack     ---------->    |    |                    |

    |                                     |    |                    |

    |  <--  response/last packet  ----    |    |                    |

    |  -------     ack     ---------->    |----+--------------------+

    |                                     |    |

    |                                     |    |

    |                                     |    | %idle.time.1 (after response, 

    |                                     |    | before new request or close)

    |                                     |    |

    |  <------   close      --------->    |----+

    |                                     |    |

    |                                     |    |


Be sure you have installed third-party tools and libraries:

unpacked the source package, type:

$ ./configure 
$ make 
$ make install


Example 1. Retrieving http network traffic in access_log format

$ justniffer -i eth0 output: - - [15/Apr/2009:17:19:57 +0200] "GET /sflogo.php?group_id=205860&type=2 HTTP/1.1" 200 0 "" "Mozilla/5.0 (X11; U; Linux i686; en-US; rv: Gecko/2009032711 Ubuntu/8.10 (intrepid) Firefox/3.0.8)" - - [15/Apr/2009:17:20:18 +0200] "GET /search?q=subversion+tagging&ie=utf-8&oe=utf-8&aq=t&rls=com.ubuntu:en-US:unofficial&client=firefox-a HTTP/1.1" 200 0 "" "Mozilla/5.0 (X11; U; Linux i686; en-US; rv: Gecko/2009032711 Ubuntu/8.10 (intrepid) Firefox/3.0.8)" - - [15/Apr/2009:17:20:07 +0200] "GET /sflogo.php?group_id=205860&type=2 HTTP/1.1" 200 0 "http://justniffer.sourceforge.net/" "Mozilla/5.0 (X11; U; Linux i686; en-US; rv: Gecko/2009032711 Ubuntu/8.10 (intrepid)Firefox/3.0.8)" - - [15/Apr/2009:17:20:18 +0200] "GET /csi?v=3&s=web&action=&tran=undefined&ei=MvvlSdjOEciRsAbY0rGpCw&e=19592,20292&rt=prt.175,xjs.557,ol.558 HTTP/1.1" 204 0 "http://www.google.it/search?q=subversion+tagging&ie=utf-8&oe=utf-8&aq=t&rls=com.ubuntu:en-US:unofficial&client=firefox-a" "Mozilla/5.0 (X11; U; Linux i686; en-US; rv: Gecko/2009032711 Ubuntu/8.10 (intrepid) Firefox/3.0.8)" - - [15/Apr/2009:17:20:07 +0200] "GET /HTTP/1.1" 200 0 "" "Mozilla/5.0 (X11; U; Linux i686; en-US; rv: Gecko/2009032711 Ubuntu/8.10 (intrepid) Firefox/3.0.8)"

Example 2. Like Example 1 but appending other fields,

For example http response time (see man page for a complete keyword list)

$ justniffer -i eth0 -a " %response.time" output: - - [22/Apr/2009:22:27:36 +0200] "GET /sflogo.php?group_id=205860&type=2 HTTP/1.1" 200 0 "http://justniffer.sourceforge.net/" "Mozilla/5.0 (X11;U; Linux i686; en-US; rv: Gecko/2009032711 Ubuntu/8.10 (intrepid) Firefox/3.0.8)" 0.427993 - - [22/Apr/2009:22:27:50 +0200] "GET /complete/search?output=firefox&client=firefox&hl=en-US&q=add+e HTTP/1.1" 200 140 "" "Mozilla/5.0 (X11; U; Linux i686; en-US; rv: Gecko/2009032711 Ubuntu/8.10 (intrepid) Firefox/3.0.8)"0.294897 - - [22/Apr/2009:22:27:51 +0200] "GET /complete/search?output=firefox&client=firefox&hl=en-US&q=add+a HTTP/1.1" 200 128 "" "Mozilla/5.0 (X11; U; Linux i686; en-US; rv: Gecko/2009032711 Ubuntu/8.10 (intrepid) Firefox/3.0.8)"0.266929 - - [22/Apr/2009:22:27:21 +0200] "GET /extern_js/f/CgJlbiswCjgVLCswDjgFLCswFjgJLCswFzgBLCswGDgDLCswITgWLCswJTjJiAEsKzAmOAQsKzAnOAAs/-wB3HvFrpXA.js HTTP/1.1" 304 0 "http://www.google.com/search?q=gnusticker&hl=en&safe=off&start=20&sa=N" "Mozilla/5.0 (X11; U; Linux i686; en-US; rv: Gecko/2009032711 Ubuntu/8.10 (intrepid) Firefox/3.0.8)" 2.025879

Example 3. Capture all tcp traffic

(add -u or -x options to encode unprintable characters):

$ justniffer -i eth0 -r output:

GET /doc/maint-guide/ch-upload.en.html HTTP/1.1
Host: www.debian.org
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:
Gecko/2009032711 Ubuntu/8.10 (intrepid) Firefox/3.0.8
Accept-Language: en,it;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: UTF-8,*
Keep-Alive: 300
Connection: keep-alive
Referer: http://www.debian.org/doc/maint-guide/
If-Modified-Since: Wed, 22 Apr 2009 19:36:31 GMT
If-None-Match: "400d604-3014-46829e160adc0"
Cache-Control: max-age=0

HTTP/1.1 304 Not Modified
Date: Wed, 22 Apr 2009 20:38:51 GMT
Server: Apache
Connection: Keep-Alive
Keep-Alive: timeout=15, max=100
ETag: "400d604-3014-46829e160adc0"
Expires: Thu, 23 Apr 2009 20:38:51 GMT
Cache-Control: max-age=86400

Example 4. Define a completely custom log format

$ justniffer -i eth0 -l "%request.timestamp %source.ip %dest.ip %request.header.host %request.url" 


06/28/11 13:30:48 i1.ytimg.com /vi/TjSk6CVN5LY/default.jpg 
06/28/11 13:30:47 i2.ytimg.com /vi/iw_nzfm1Vts/default.jpg 
06/28/11 13:30:47 static.sourceforge.net /css/phoneix/jquery.cluetip.php?secure=0 
06/28/11 13:30:48 static.sourceforge.net /sfx.js 
06/28/11 13:30:49 static.sourceforge.net /include/coremetrics/v40/eluminate.js 
06/28/11 13:30:51 c.fsdn.com /sf/images/phoneix/grad_white_dual_100.png 

Example 5. Read from a capture file

NOTE: capture file must be performed with unlimited snaplen for catching whole packets. Justniffer can work only works on pcap files with whole packets. tcpdump command example: tcpdump -w /tmp/file.cap -s0 -i ath0

$ justniffer -f /file.cap

Example 6. Parameters for setting a more precise formatting

Many keyword has parameters for setting a more precise formatting:

$ justniffer -i eth0 -l "%request.timestamp %request.header.host %request.url %response.time"  output:

06/28/11 13:39:40 static.sourceforge.net /css/phoneix/print.css?secure=0&20080417-1657 0.162620

you can specifying timestamp formatting

$ justniffer -i eth0 -l "%request.timestamp (%B %d %Y %H:%M:%S) %request.header.host %request.url %response.time"


June 28 2009 13:39:40 static.sourceforge.net /css/phoneix/print.css?secure=0&20080417-1657 0.162620

or to print the string NoHostFound if the %request.header.host cannot be valued

$ justniffer -i eth0 -l "%request.timestamp %request.header.host (NoHostFound)%request.url %response.time" 


06/28/11 15:10:28 www.google.com /ig?hl=en 0.116146
06/28/11 15:10:28 NoHostFound/ig?hl=en 0.116146 many keywords have their own formatting string. A generic option ( -n) can be used for setting a default "not found" string: a string that must replace the keyword if it cannot be valued. for example if request.header.[headername] is not found or if connection.time cannot be applicable. Anyway, if a "no found" string is provided as keyword parameter (for those that expect it), it will override the -n option

$ justniffer -i eth0 -l "%request.timestamp %request.header.host(NoHostFound) %request.header.host %request.url %response.time" -n N/A

output: 06/28/11 15:10:28 www.google.com www.google.com/ig?hl=en 0.116146 06/28/11 15:10:28 NoHostFound N/A/ig?hl=en 0.116146

Example 7. Capture only http traffic

the -p option let you to specify a tcpdump compatible filter (see pcap-filter(7)): “port 80 or port 8080” capture only http traffic (usually using tcp port 80 and 8080)

$ justniffer -i eth0 -r -p "port 80 or port 8080"

Example 8. Extend with an external executable

the -e option let you to specify an external executable (usually a script) to which , for every log, the output will be redirect to. If you want to perform complex extraction operations, you can write your own script that will receive from the standard input all content specified by the -l option. A complete ad useful example is provided with justniffer-grab-http-traffic $ justniffer -l “%response” -e ./myscript.sh -i ath0


# myscript.sh 
# example script (print all lines containing "href" string)

while read inputline
anchors=`echo "$inputline" | grep href`
if [ "$anchors" != "" ]; then
echo $anchors;

Example 9. Capture smtp traffic (usually using tcp port 25)

$ justniffer -i eth0 -r -p "port 25"


220 plecno.com ESMTP Postfix (Ubuntu)

EHLO unknown.localnet
250 DSN                

MAIL FROM:<xxxx.xxxx@xxx.xxx> SIZE=1079
RCPT TO:<yyyyy.xxxx@yyyy.xxx>             
250 2.1.0 Ok                                   
250 2.1.5 Ok                                   
354 End data with <CR><LF>.<CR><LF>        

From: Oreste Notelli <xxxx.xxxx@xxx.xxx>
Organization: Plecno
To: yyyyy.xxxx@yyyy.xxx
Subject: test
Date: Wed, 22 Apr 2009 22:46:16 +0200
User-Agent: KMail/1.11.2 (Linux/2.6.27-8-generic; KDE/4.2.2; i686;
; )
MIME-Version: 1.0
Content-Type: multipart/alternative;
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Message-Id: <200904222246.17292.xxxx.xxxx@xxx.xxx>

Content-Type: text/plain;
Content-Transfer-Encoding: 7bit


Content-Type: text/html;
Content-Transfer-Encoding: 7bit

<meta name="qrichtext" content="1" />
<style type="text/css">p, li { white-space: pre-wrap;
<body style=" font-family:'DejaVu Sans'; font-size:8pt;
font-weight:400; font-style:normal;">
250 2.0.0 Ok: queued as 33E7235C21A

221 2.0.0 Bye

Example 10. Trace performances

The following keywords are used to obtain logs that give an overview on the performance of services based on HTTP protocol measuring connection time, response time, tcp connection timeouts, keep alive requests, etc. (see man for more information)

$ sudo justniffer -i eth0 -u -p "port 80 or port 8080" -l "%request.header.host %request.url %connection.time %idle.time.0  %request.time %response.time.begin %response.time.end %idle.time.1 %connection %close.originator"

Example 11. Grep keywords

The “grep keywords”can be used to capture portions of text using regular expressions. In this example we want to collect:

the url from the request header by the regular expression [^\s][\s]([^\s]) and the content type from the response header by the regular expression Content-Type:(\s)([^\r]*)

$ sudo justniffer -l "%request.header.grep([^\s]*[\s]*([^\s]*)) %response.header.grep(Content-Type:(\s)*([^\r]*)) %source.ip" -i eth0


/ text/html
/plecno_res/src/effects.js application/javascript
/plecno_res/src/slider.js application/javascript
/plecno_res/src/effects.js application/javascript
/plecno_res/src/builder.js application/javascript
/plecno_res/src/effects.js application/javascript

see MAN