Varnish, get your patch on.
Varnish is a "bad ass" new HTTP caching accelerator. It's developed by some crufty old BSD hacker and has a lot of Linux users. By and large, it has ignored Solaris. This sort of neglect isn't malicious, it is just neglect... you know: "out of sight, out of mind."
Perhaps one day, the Solaris networking team (or someone else) will satisfy this pretty abysmal shortcoming: BugID 4641715.