SmartSniff is a network monitoring utility that allows you to capture TCP/IP packets that pass through your network adapter, and view the captured data as sequence of conversations between clients and servers. You can view the TCP/IP conversations in Ascii mode (for text-based protocols, like HTTP, SMTP, POP3 and FTP.) or as hex dump. (for non-text base protocols, like DNS)
SmartSniff provides 3 methods for capturing TCP/IP packets :
- Raw Sockets (Only for Windows 2000/XP or greater): Allows you to capture TCP/IP packets on your network without installing a capture driver. This method has some limitations and problems.
WinPcap Capture Driver: Allows you to capture TCP/IP packets on all Windows operating systems. (Windows 98/ME/NT/2000/XP/2003/Vista) In order to use it, you have to download and install WinPcap Capture Driver from this Web site. (WinPcap is a free open-source capture driver.)This method is generally the preferred way to capture TCP/IP packets with SmartSniff, and it works better than the Raw Sockets method.
Microsoft Network Monitor Driver (Only for Windows 2000/XP/2003): Microsoft provides a free capture driver under Windows 2000/XP/2003 that can be used by SmartSniff, but this driver is not installed by default, and you have to manually install it, by using one of the following options:
- Option 1: Install it from the CD-ROM of Windows 2000/XP according to the instructions in Microsoft Web site
- Option 2 (XP Only) : Download and install the Windows XP Service Pack 2 Support Tools. One of the tools in this package is netcap.exe. When you run this tool in the first time, the Network Monitor Driver will automatically be installed on your system.
Microsoft Network Monitor Driver 3: Microsoft provides a new version of Microsoft Network Monitor driver (3.x) that is also supported under Windows 7/Vista/2008. Starting from version 1.60, SmartSniff can use this driver to capture the network traffic.The new version of Microsoft Network Monitor (3.x) is available to download from Microsoft Web site.Notice:If WinPcap is installed on your system, and you want to use the Microsoft Network Monitor Driver method, it’s recommended to run SmartSniff with /NoCapDriver, because the Microsoft Network Monitor Driver may not work properly when WinPcap is loaded too.
In order to start using SmartSniff, simply copy the executable (smsniff.exe) to any folder you like, and run it (installation is not needed).
After running SmartSniff, select “Start Capture” from the File menu, or simply click the green play button in the toolbar. If it’s the first time that you use SmartSniff, you’ll be asked to select the capture method and the network adapter that you want to use. If WinPcap is installed on your computer, it’s recommended to use this method to capture packets.
After selecting the capture method and your network adapter, click the ‘OK’ button to start capturing TCP/IP packets. while capturing packets, try to browse some Web sites, or retrieve new emails from your email software. After stopping the capture (by clicking the red stop button) SmartSniff displays the list of all TCP/IP conversations the it captured. When you select a specific conversation in the upper pane, the lower pane displays the TCP/IP streams of the selected client-server conversation.
If you want the save the captured packets for viewing them later, use “Save Packets Data To File” option from the File menu.
SmartSniff provides 3 basic modes to display the captured data: Automatic, Ascii, and Hex Dump. On Automatic mode (the default), SmartSniff checks the first bytes of the data stream – If it contains characters lower than 0x20 (excluding CR, LF and tab characters), it displays the data in Hex mode. otherwise, it displays it in Ascii mode.
You can easily switch between display modes by selecting them from the menu, or by using F2 – F4 keys. Be aware that ‘Hex Dump’ mode is much slower than Ascii mode.
Starting from version 1.35, there is a new mode – ‘URL List’. This mode only display the URL addresses list (http://…) found in the captured packets.
Exporting the captured data
SmartSniff allows you to easily export the captured data for using it in other applications:
- The upper pane: you can select one or more items in the upper pane, and then copy them to the clipboard (You can paste the copied items into Excel or into spreadsheet of OpenOffice.org) or save them to text/HTML/XML file (by using ‘Save Packet Summaries’).
The lower pane: You can select any part of the TCP/IP streams (or select all text, by using Ctrl+A), copy the selected text to the clipboard, and then paste it to Notepad, Wordpad, MS-Word or any other editor. When you paste the selected streams to document of Wordpad, OpenOffice.org, or MS-Word, the colors are also transferred.Your can also export the TCP/IP streams to text file, HTML file, or raw data file, by using “Export TCP/IP Streams” option.
Capture and Display Filters
Starting from version 1.10, you can filter unwanted TCP/IP activity during the capture process (Capture Filter), or when displaying the captured TCP/IP data (Display Filter).
For both filter types, you can add one or more filter strings (separated by spaces or CRLF) in the following syntax:
[include | exclude] : [local | remote | both] : [tcp | udp | tcpudp | icmp | all] : [IP Range | Ports Range]
Here’s some examples that demonstrate how to create a filter string:
Display only packets with remote tcp port 80 (Web sites):include:remote:tcp:80
Display only packets with remote tcp port 80 (Web sites) and udp port 53 (DNS):include:remote:tcp:80include:remote:udp:53
Display only packets originated from the following IP address range: 192.168.0.1 192.168.0.100:include:remote:all:192.168.0.1-192.168.0.100
Display only TCP and UDP packets that use the following port range: 53 – 139:include:both:tcpudp:53-139
Filter most BitTorrent packets (port 6881):exclude:both:tcpupd:6881
Filter all ICMP packets (Ping/Traceroute activity):exclude:both:icmp
Notice: A single filter string must not include spaces !
Starting from version 1.10, a new option was added to ‘Advanced Options’ section – ‘Live Mode’. When SmartSniff capture packets in live mode, the TCP/IP conversations list is updated while capturing the packets, instead of updating it only after the capture is finished. Be aware that “Live Mode” requires more CPU resources than non-live mode. So if your computer is slow, or your have a very high traffic on your network, it’s recommended to turn off this option.
Starting from version 1.20, you can also view the content of each TCP/IP conversation (in the lower pane) while capturing the packets. However, if the TCP/IP conversation is too large, you won’t be able to watch the entire TCP/IP conversation until the capture is stopped.
Viewing process information
Starting from version 1.30, you can view the process information (ProcessID and process filename) for captured TCP packets. However, this feature have some limitations and problems:
- Process information is only displayed for TCP packets (It doesn’t work with UDP)
- Process information may not be displayed for TCP connections that closed after short period of time.
- Retrieving process information consume more CPU resources and may slow down your computer. It’s not recommended to use this feature if you have intensive network traffic.
- Process information is currently not saved in ssp file.
In order to activate this feature, go to ‘Advanced Options’ dialog-box, check the “Retrieve process information while capturing packets” option and click the ‘OK’ button. 2 new columns will be added: ProcessID and Process Filename. Start capturing, and process information will be displayed for the captured TCP conversations.
The structure of .ssp file (SmartSniff Packets File)
The structure of .ssp file saved by SmartSniff is very a simple. It contains one main header in the beginning of the file, followed by sequence of all TCP/IP packets, each of them begins with a small header.
The main header structure:
00 – SMSNF200 signature.
08 – (2 bytes) The number of bytes in the header (currently 4 bytes for the IP Address)
0A – (4 bytes) IP Address
Header of each packet:
00 (2 Bytes) packet header size (currently 0x18 bytes)
02 (4 Bytes) number of received bytes in packet.
06 (8 Bytes) Packet time in Windows FILETIME format.
0E (6 Bytes) Source Mac Address.
14 (6 Bytes) Dest. Mac Address.
1A The remaining bytes are the TCP/IP packet itself.