Linux Download dependencies behind proxy requiring authentication

Hello, I can’t seem to download dependencies.

Failed to download ‘’ to ‘/tmp/tmp3693dc6a.tmp’: The remote server returned an error: (407) Proxy Authentication Required. (WebException)

My http_proxy, https_proxy, and HTTP_PROXY environment variables are working for apt-get, git, wget, etc. They are of the format http://username:password@url:port

I also tried to run ./ with the --proxy argument but that failed similarly.

amigo- on the UE4Linux freenode IRC channel helped me identify the location in the source code that might be responsible. Neither of us are familiar enough with Mono’s Network stack to know if it accepts proxy URLs of the above format. If not, then it might be necessary to parse the URL and add

Request.Proxy.Credentials = new NetworkCredential("username", "password");

Or, for the ./ to accept the --user and --pass arguments.

Thank you.

I connected to the proxy-less GUEST WiFI by bridging through a different computer and was able to download and build. It’d still be nice for this to be fixed but it is no longer a problem for me.


Sorry I haven’t had a chance to look into this yet, there’s just too many things to do. :slight_smile:

It should be possible to fix up the C# code to allow inclusion of username/password parameters in the command line.

Hopefully someone from Epic can do this, or perhaps if I can find time, I’ll do a PR to epic/master.

For anyone else landing here, looks like you can now run:

.\ --proxy="myproxy:8080" --proxy-user="myusername" --proxy-password="mysupersecurepassword"


export HTTP_PROXY="myproxy:8080"
.\ --proxy-user="myusername" --proxy-password="mysupersecurepassword"