Under the hood, `n` uses `curl` or `wget` for the downloads. `curl` is used if available, and `wget` otherwise. Both `curl` and `wget` support using environment variables or startup files to set up the proxy.
## Using Environment Variable
You can define the proxy server using an environment variable, which is read by multiple commands including `curl` and `wget`:
If you use `sudo` to run `n`, you need to do something extra to make the environment variables available. A simple way is to use `-E` (`--preserve-env`):
Your proxy server may supply its own ssl certificates for remote sites (as a man-in-the-middle). If you can not arrange to trust the proxy in this role, you can turn off (all) certificate checking with `--insecure`. e.g.
n --insecure --lts
Another possible work-around for certificate problems is to use plain http by specifying a custom node mirror:
export NODE_MIRROR='http://nodejs.org/dist'
export http_proxy='http://host:port/path'
n --lts
## Startup Files
An alternative to using an environment variable for the proxy settings is to configure a startup file for the command.
Example `~/.curlrc` ([documentation](https://ec.haxx.se/cmdline-configfile.html))
proxy = http://host:port/path
proxy-user = user:password
# If need to disable certificate checks
--insecure
Example `~/.wgetrc` ([documentation](https://www.gnu.org/software/wget/manual/html_node/Wgetrc-Commands.html#Wgetrc-Commands))
https_proxy = http://host:port/path
proxy_user = user
proxy_password = password
# If need to disable certificate checks
check_certificate = off
## Troubleshooting
To experiment and find what settings you need, use `curl` (or `wget`) directly with the node mirror and check the error messages.
For these examples there is a proxy running on localhost:8080 which does not require authentication, but the certificates it offers
are not trusted.
First try fails because of the certificates and `curl` helpfully explains:
