The paper concerns about basic Microsoft ISA server and Linux Squid Server configuration As a lot of technicians switch between ISA server and Squid server, I decided to write this paper to present some reference when configuring ISA and Squid. There a lot of issues that not covered, and you can go to the manual of ISA server and Squid server for detailed configuration of ISA and Squid. The paper is composed from two parts 1. Microsoft ISA server 2004 Configuration 2. Linux Squid Server Configuration Note that, this work was done without proper simulation, because of the lack of resources, as testing firewall configuration requires many computers, with one of them should have many network cards. Also the ISA server is not used in the computer center now.