ok thx, the /etc/sysconfig/networking/devices/ifcfg-eth0 files doesn't exist on my OS that's why i found an other way to resolv it.
for my Sun Server with Solaris 8 :
I added an entry in /etc/hosts
xxx.xxx.xxx.xxx 'hostname'2
I already had the /etc/hostname.eri0
I created /etc/hostname.eri0:1
with in this file the 'hostname'2
and it's working