When saving the connection info in mstsc to a .rdp file the configured remote computer name will appear like this:
full address:s:rds.contoso.com
However, when downloading .rdp files from RD Web Access, the files will have the target host name stored twice:
full address:s:rds.contoso.com
alternate full address:s:rds.contoso.com
When grepping the alternate full address string in the mstscax.dll files from the last 15 years, it seems that this setting was introduced in mstsc version 6.1.7600.16385 (Windows 7, RTM), which would be RDP protocol version 7.0.
I could not really find any documentation that clearly explains what the difference between these two settings is.
Below I'm quoting the only authentic (but vacuous) description I could find on https://docs.microsoft.com/en-us/windows/desktop/api/rdpappcontainerclient/nf-rdpappcontainerclient-iremotedesktopclientsettings-setrdpproperty
"alternate full address" (String)
Specifies an alternate name or IP address of the remote computer that you want to connect to."full address" (String)
Specifies the address of the computer being connected to.
Yay! ... Not helping.
Some people incorrectly suggested that it is kind of a primitive fall back or redundancy mechanism, meaning that mstsc would first try to connect to full address and fall back to alternate full address if the former connection fails or the other way around.
I've prepared some rdp files with in order to find out how mstsc handles these two values and the conclusion is that if alternate full address is set then full address will be completely ignored, also there will be no fall back whatsoever if alternate full address cannot be resolved or reached.
That leaves me at my actual question:
What is the reason for the introduction of the alternate full address rdp file setting in RDP 7.0 and what can it be used for?
