Serve *only* from cache for particular user-agents

[Darren Pilgrim]

On 2/21/2014 7:25 AM, rge3 wrote:
> I havne't found any ideas for this and thought I might ask here.  We have a
> fairly straightforward proxy_cache setup with a proxy_pass backend.  We
> cache documents for different lengths of time or go the backend for what's
> missing.  My problem is we're getting overrun with bot and spider requests.
> MSN in particular started hitting us exceptionally hard yesterday and
> started bringing our backend servers down.  Because they're crawling the
> site from end to end our cache is missing a lot of those pages and nginx has
> to pass the request on through.

Are they ignoring your robots.txt?