This may allow full search results, but the links still won't work, as the firewall blocks 'undesirable' URLs.<p>So the proxy would also need to convert URLs in the returned pages to link to proxied URLs, and to provide a proxy service for these 'undesirable' URLs.<p>If content filtering is used, then it would also need to strip out 'undesirable' words to prevent the whole page from being blocked based on its content rather than its URL.<p>I suppose a central service could be provided to provide all the proxy servers with the uptodate list of URLs that need proxying, and words that must be removed.<p>All this seems to me to be very possible, although it's probably a little more than you were thinking.