The Sun Netra brand has been used for a variety of server computers from Sun Microsystems. These servers used for various purposes such as telecommunications applications.
The Sun Netra ATCA CP3220 and CP3250 blades needs a special driver package for the Sun 10 Gigabit Ethernet device. That driver package is called a kmod package and it can be downloaded from Sun's website. Some Linux distribution such as RHEL v5.3+ have included the same in default installation.
You can download the same from here.