Correct way to raise immediate error in VCL

Paul A. Procacci pprocacci at
Thu Mar 8 07:37:16 CET 2012

I don't know the answer to your question as I'm still using the latest varnish 2.x in production,
but you can see exactly what your vcl produces by `varnish -C -f /path/to/vcl_file`.

Hope that helps.


On Wed, Mar 07, 2012 at 02:48:23PM +0000, George wrote:
> 3.0 Docs state that from vcl_recv "The vcl_recv subroutine may terminate
> with calling return() on one of the following keywords:" ... error code
> [reason]. This implies a syntax of return( error 404 "Not Found" ); -
> which I believe is incorrect and didn't work when I tried it. There are
> a number of examples of throwing errors - usually something like   error
> 404 "Not Found" that I know work .
> However, I can find no definitive statement that this method causes an
> IMMEDIATE return from vcl_recv. The reason I need clarification is that
> I am tracking an issue that seems to indicate that processing continues
> after an error is called and am seeing urls appearing in the backend
> server logs that indicate subsequent pipe commands may have been honored
> despite the error call.
> Could someone clarify - is calling error 404 "Not Found"; sufficient to
> cause all further processing to cease and a subroutine return to be
> implicitly carried out - or is something more specific required like..
> (VCL Snippit)
>          #block unauthorized access to this site
>          if (!client.ip ~ authorized) {
>            error 404 "Not Found.";
>            return (error);
>          }
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