Let's say we have Varnish configured with Apache as a backend.
For some odd reasons, some clients send custom HTTP headers that are badly formed because they have a space before the header's colon (eg. "X-CUSTOM : value"), causing a 400 bad request on Apache.
Is it possible to deal with it on the Varnish side to sanitize headers, removing the extra space before the colon?
If you know another tool than Varnish that can easily do this job it's ok for me too.