Red Hat provides direct download links. On your Linux server, you can use:
: Log in to the Red Hat Customer Portal to access software downloads. redhat 6 iso download
If you need RHEL 6 compatibility for old software, consider containerization instead of running RHEL 6 on bare metal. Red Hat provides direct download links
I understand you're looking for a Red Hat Enterprise Linux (RHEL) 6 ISO. However, I should clarify a few important points: redhat 6 iso download