If you're in trouble and cannot find an answer to a question which goes beyond Stack Overflow...
If you have a not-so-usual solution for your problems but need to justify it to your boss...
If you like to think on your own rather than blindly follow "common wisdom" and "profound truth"...
...then 'No Bugs' Hare on Soft.ware might be the right place for you.
Your mileage may vary. Batteries not included

Network programming is one field which everybody uses but very few people really know in depth. Our IT Hare did write a software which processes billions of network packets per day; moreover, they’ve done it in a very robust and efficient manner. And last but not least, they’re ready to share their experience :-)

Network Programming, page 2:

Network Programming: Socket Peculiarities, Threads, and Testing

Quote: “I am not saying that this architecture is the only viable one, but it does work for TCP for sure (and performs reasonably well too)”
Another Quote: “The whole task of optimizing performance beyond, say, 20-50K packets/second per box tends to be Quite Elaborated, and involves quite a few things which are platform- and hardware-dependent.”
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UDP for games – security (encryption and DDoS protection)

Quote: “Yes, you DO need to encrypt your UDP traffic. And no, using UDP is NOT a valid excuse to skip encryption”
Another Quote: “Personally, I prefer to think of it as of insurance – when I’m paying my premiums in hope that my money will go to waste.”
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UDP from MOG Perspective

Quote: “you may think of UDP as of an analog of good old C: you can do pretty much everything, but it is not because the language helps you – it is rather because it doesn’t stand in the way :-)”
Another Quote: “As most of the routers (including pretty much every backbone router out there) are not configured to support multicast, it makes multicast over the public Internet hopeless :-(“
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Unity 5 vs UE4 vs Photon vs DIY for MMO

Quote: “You can still use HLAPI despite its shortcomings”
Another Quote: “If you’re using one of the engines above (and not your own one), and your game requires Client-Driven Development Flow, you may want to start with a single-player Unity 5, or with a single-player UE4.”
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IDL: Encodings, Mappings, and Backward Compatibility

Quote: “Modifying generated code usually qualifies as a Really Bad Idea”
Another Quote: “How much can be gained by each of such specialized encodings – still depends on the game, but if you can try-and-test a dozen of different encodings within a few hours – it will usually allow you to learn quite a few things about your traffic (and to optimize things both visually and traffic-wise too).”
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