Safari ignores Hosts file

Hi,

My problem is with a collection of Macs (running 10.6.8) in a Windows network with LDAP and Workgroup Manager from a Mac server.

I'm trying to use entries in a hosts file to bypass DNS and our proxy server for certain domains. The entries in the hosts file are correct, using ping I can see they are correct. However Safari ignores this hosts file.

In System Preferences I have proxies set for HTTP and HTTPS, despite setting the same domains for "Bypass proxy settings for these Hosts & Domains", Safari still ignores the hosts file.

Chrome also behaves in the same manner.

Oddly, Firefox acts differently, but only when manually entering the proxy settings (and the subsequent bypass settings). I briefly thought that I could use Firefox as a workaround, and then realised Firefox only stores these proxy settings per user and not administratively for any user logging onto the Mac.

Am I missing something?

Thanks, Matt