This problem was written by Alex Studer, a guest problem writer.
You've been trying to get into the servers of DynamicSystems, a company that...well, no one really seems to know what they do.
You've discovered that their employees connect to a link server and download some secret information from there, which DynamicSystems refers to as a "flag".
Luckily, you managed to find a copy of a document describing how to communicate with their link server. You also found a copy of the link server's source code, though you don't think it'll be very helpful.
Oh, and one more thing. Don't forget the official motto of DynamicSystems: "Since 2014: Our hearts bleed for our clients!"