Very often we get people asking in forums on how to check what files are being downloaded to the computer by a web installer. One example is when you want to install Google Chrome, the whole process of downloading and installing seems to be done automatically without going through the traditional method of asking you to download a single executable file and run it to install. You don’t even know the direct link to download the files. The solution to see what is happening in background is to use a packet sniffer. Packet sniffing and decoding using advanced tools such as WireShark may not be easy for everyone, hence, Nir Sofer from www.nirsoft.net created a really simple tool to do that.
WebSiteSniffer is a free and portable packet sniffing tool that captures files downloaded by your computer and saves them to the base folder that you get to define in the Options. Although WebSiteSniffer is a portable tool, you may need to install packet capturing drivers such as WinPcap or Network Monitor Driver if the Raw Sockets method doesn’t work for you.
I tried the Raw Sockets capture method and it is really buggy. There are times that it doesn’t capture anything at all even though I run it as Administrator or I get the error “Failed to start capturing packets from the current network adapter!”. So far WinPcap or Network Monitor Driver 3.x worked flawlessly but I personally prefer to use WinPcap because I have it installed on my computer for many years and never had any problems.
At the WebSiteSniffer Options, you get to choose the folder where all the files are downloaded to and the file types that you want to download. Installers in executable extensions (.exe .msi) are grouped into “All Others”. Next is to select the capture method where by the capture method is only selectable if the drivers are installed. Finally, select the network adapter that you want to sniff and capture. Once you finished configuring the options, click on the green play icon at the menubar to start capture. To me, the WebSiteSniffer user interface doesn’t really provide any important information other than the total count and total size that it has downloaded. What matters most is the captured files on the base folder.
Although the name of the software sounds like it can only work on web browsers to capture on websites, it also works on web installers such as AVG, Google Chrome and etc. There are limitations to WebSiteSniffer which is it cannot capture HTTPS secured website as they are encrypted. It also reports of possible file corruption when downloading a large file with a fast Internet connection. When that happens, URLSnooper2 comes to play by revealing the hidden URL so you can manually download the file from your web browser.
Do note that WebSiteSniffer works very differently from URLSnooper2 which I normally recommend. WebSiteSniffer produces the “files” while URLSnooper2 produces “URLs” that are downloaded by your computer.