Updater and Server
FoxitUpdater.exe: When you click on "Check for Update..." in About Foxit PDF Editor box.
FoxitUpdater.exe is awoke and starts to connect update server to get resources. The updater is initially stored on the following place along with the installing:
..\Program Files (x86)\Foxit Software\Foxit PDF Editor
When the "check for updates" is triggered, the FoxitUpdater.exe will be copied to the following place:
..\Users\YourAccountName\AppData\Roaming\Foxit Software\Addon\Foxit PDF Editor
Update servers: The FoxitUpdater.exe uses HTTP to access server. This involves the following two servers:
us-request.foxitservice.com: this is the request server.
cdn0X.foxitsoftware.com: this is the response server where the setup file is actually stored for downloading.
Once the Foxit Updater is commanded to check for updates, it immediately sends an HTTP request to the request server “who” returns without prompting with specific information and show you in the updater window if there is an updated version available or not. If there is not a greater version, it simply drops you a message " there are not updates available". If there is a greater version, it presents the update title in the Available Updates list. Upon the update is added and asked to download, it starts to download by connecting to the download server.
Both HTTP request and response use the default TCP port 80.
Note: In future, Foxit Updater will use HTTPs to connect server. Then the request port 443 will be used instead and the response will be still default to 80.
The following section takes examples when I check for updates inside Foxit PDF Editor:
If there is not a greater version on the server, the Updater shows you:
If there is a greater version on the server, it will present the update title in the Available Updates list as the below figure.( The update for Foxit PDF Editor V12.0 is just an example)
When the "Foxit PDF Editor Upgrade" in the above figure is checked and the Download and Install button is triggered, the Updater connects to the response server and the downloading starts.