> On Nov 9, 2017, at 12:53 PM, Tobi <tobs...@brain-force.ch> wrote: > > I have a content filter running in prequeue mode to which postfix talks > via smtpd_proxy_filter.
Best to call that a "proxy filter" to avoid confusion. > Runs fine, but ;-) it seems to me that postfix header checks are > evaluated after the msg has been processed by the content filter. Header checks happen after proxy filters and before content filters. > Is it somehow possible to tell postfix to run those checks **before** > msg is passed to the content filter? Only by using a content filter. You can of course use all three: proxy filters, header checks and content filters. They will be processed in that order. -- Viktor.