On Tue, Sep 15, 2015 at 01:58:27PM +0200, POSTFIX MAIL wrote: > The only difference between the 2 tests is the debug_peer_list parameter > (postfix, content filter, filter, message are the same). > > If the filter is buggy, the result should be the same but this is not the > case here. So, I would like to understand why the behaviour is different > once I enable debug on postfix ...
The filter is buggy, at least to the extent of not implementing command pipelining correctly. A non-buggy filter will handle semantically identical input largely identically. A buggy filter might depend on the details of inter-packet timing, the latency of the syslog service under increased load, ... -- Viktor.