I own a Z87-G45 which has Killer ethernet.
The Killer ethernet is known to cause issues... I had to update the drivers recently because Steam's In-Home-Streaming did not detect anything.

I just looked up this "Killer Ethernet" and it seems that it is also a Qualcom Atheros chipset under the hood ...

I'm really annoyed by this bug, so I spent the whole day narrowing the issue down.

As I was already saying, I'm able to connect to our server from my Macbook and my Notebook with Linux on it, but I was not able to connect to it from my Gaming PC with Windows on it.
To work around this issue I now ...

Personally, I don't think that my ISP is blocking something. If I use my Macbook, I can connect to our server without an issue. If I use my Notebook with Linux on it, I can connect to our server, but if I use my Windows machine, it gets stuck at 100%, 100% of the time.

And a few of my friends ...

I just tested a few server - client configurations. And what I found out is:

Linux Client - Linux Server -> is working normally.
Mac Client - Linux Server -> is working normally.
Windows Client - Linux Server -> NOT WORKING.

Linux Client - Windows Server -> Sometimes not working

And it appears ...

Hey,
I have this issue too...
We are playing on a map that by now uses around 35mb of space.
The host uses Linux and I (as a Client) am on a Windows machine.

I'll attach the log file, maybe it useful for you!

Hi,
were you able to find a solution for this issue?
Because i have the same issue with the latest version of factorio...
I cannot connect to the server, it always stops downloading at 100%...

Thanks