If you are planning to deploy ESXi 5.5 today, you must be aware of its support status: September 19, 2018. End of Technical Guidance: September 19, 2020.
ESXi 5.5 was designed for older hardware. Check the VMware Compatibility Guide to ensure your CPU and NIC are supported. vmware esxi 5.5 iso download
Major hardware vendors like Dell , HP , and Lenovo often host customized ESXi 5.5 images designed for their specific server hardware. These are typically the easiest "official" versions to find. If you are planning to deploy ESXi 5
You can find specific builds such as ESXi 5.5 Update 2 or Update 3 on their support site. Check the VMware Compatibility Guide to ensure your
If you have an existing account or "entitlement" from a past purchase, you can try searching the Broadcom Support Portal. However, older versions are frequently hidden or restricted to those with active support contracts.