PDFs provided by datatracker.ietf.org don't have hyperlinks. html rfc URLs on tools.ietf.org (which had links to PDF) now redirects to datatracker.ietf.org<p>PDFs from tools.ietf.org are still available on their previous URLs. like for rfc791 it is <a href="https://tools.ietf.org/pdf/rfc791.pdf" rel="nofollow">https://tools.ietf.org/pdf/rfc791.pdf</a>