Which process is on which port....

Is there a way in Solaris to find which process is using which port?

The simplest way it to install lsof. The alternative in Solaris 10 is to run pfiles on each process.

Thanks. So basically there's not a way to do it without installing something?

Also I found that pfiles exists on 5.8 and 5.9. This could work for me.

I don't believe that useful port information was added until Solaris 10.