Thanx for info, but i've already read this manual. If possible i'd like to have some configuration example of ip_conntrack_h323 and nat_conntrack_h323. I have another problem when compile with p-o-m the kernel, the following message results: xxxxx doesn't look like a kernel tree to me. My system use Redhat 9 with kernel version 2.4.20-31.9, the Source RPM installed in the directoy /usr/src/redhat/SOURCES but there isn't the Makefile. How resolve this problem ?? Thank you for help (and sorry for my bad english) Maurizio Li Vigni