In any system, the network firewall is the main feature which will be protecting the system from getting attacked from any illegal intruders who will try to hack the system and steel the information from the network. These firewalls have been involving in the optimization that has to be done when any other tries to come through the other firewall and sharing the information will improve the network performance very well. Firewall will be mainly concentrating on intra firewall and also inter firewall optimization that will be helpful to improve the security of the network. Previously, there has been the use of cross-domain privacy preserving cooperative firewall policy optimization protocol. But there is no improvement that made a lot of difference in the native methods used. So we propose secure multi-party computation of union which will be improving the firewall optimization and also improving the security very well when compared to the all the previous methods.