The string "red hat enterprise linux 5.7 x64 iso 84" appears to combine a real, historical RHEL version (5.7, 64-bit) with a suspicious or erroneous suffix "84" . This might be a typo, a misinterpretation of a filename (e.g., part of a split archive or a label like “build 84”), or—more likely—a reference to an unofficial, possibly malicious repackaging circulating on non-Red Hat sites.
If you are working with this specific version, I can help you further if you tell me:
When you find the ISO, immediately take a checksum (md5sum/sha256sum) and store it alongside the file. In five years, when you need to rebuild again, you will need to verify that the bits haven't rotted. Long live RHEL 5.7.
It is irresponsible to write about RHEL 5.7 without addressing security.