Failed to syncronize cache for repo 'fedora' ... (possible proxy issues)

Question

I just started on a fedora build. Just managed to add myself to the sudoers file, so now I am attempting to grab vim. I do a

sudo dnf install vim

and get hit with the following error message.

Error: Failed to synchronize cache for repo 'fedora' from 'https://mirrors.fedoraproject.org/metalink?repo=fedora-23&arch=x86_64': Cannot prepare internal mirrorlist: Curl error (6): Couldn't resolve host name for https://mirrors.fedoraproject.org/metalink?repo=fedora-23&arch=x86_64 [Could not resolve host: mirrors.fedoraproject.org]

To me, this looks like a proxy issue. I attempt this

export http_proxy="<my proxy>"

And then retry

sudo dnf install vim

Same response. I know the proxy is correct, as it worked for me on a previous RedHat build, so can someone recomend me the next steps to try here?

Solution

After some research, I found that I needed to open

/etc/dnf/dnf.conf

and add the line

proxy=http://<my_proxy>:<port>

Simply setting the http_proxy in the bash shell was not enough.