If Solaris does not natively recognize the network interface circuitry that is inside your system,
then prtconf will not show it either.
You need to determine what network chipset is there, then compare it to the HCL, the Hardware Compatibility list.
There will be a HCL for Solaris 10 and there will be a HCL for Solaris 11.
So far, you have not told us anything useful, for anyone to help you further.
You did not mention which Solaris you are installing, you didn't tell us what kind of a system you have, and you didn't mention what NIC is in your system.
If you see the NIC on the HCL and it requires third party drivers, there will be a link to those drivers. If the NIC does not appear there at all, you will have to go buy and install one that is+ compatible, then install whatever drivers it needs to make it work.
By the way, this same question has been asked many times over the years, and the answer is always the same. You could have gotten your answer by reading all the forums and you wouldn't have had to make your own post.
You're right!!!. When you say "determine what network chipset". What command I run to see the chipset, I know that the Network card is integreted into the motherboard. Or You suggest me to open my desktokp and see the mark of the moderboard. It could help you?
The version of the solaris that I installed in my x386 is Solaris 10, but let me confirmed what version and kernel is installed (uname -a and cat /etc/release)
Also rukbat, do you need to any another information, please give me the command to use.