varnish is the server-side alternative to Squid, written primarily with speed in mind, and with a look to implementing full ESI-support in a future release. . The goal of the Varnish project is to develop a state-of-the-art, high-performance HTTP accelerator. . Varnish is targeted primarily at the FreeBSD 6 and Linux 2.6 platforms, and will take full advantage of the advanced I/O features offered by these operating systems.