At work we use SLES 11 which has quite old versions of openssl and installed certificates. I was getting certificate errors trying to install rust with the rustup tool.

I tried searching for any help at all but in the end I followed the following advice:

• download a more recent certificate bundle (e.g. from certifi or mozilla)
• set the environment variable SSL_CERT_FILE to point to this new file

This works for both rustup and cargo meaning I can develop with rust on my work machine.