12.7.8 Specifying Maximum Length Header

Keywords: maxprocchars

Processing of long header lines containing lots of addresses can consume significant system resources. The maxprocchars keyword is used to specify the maximum length header that the MTA can process and rewrite. Messages with headers longer than this are still accepted and delivered; the only difference is that the long header lines are not rewritten in any way. A single integer argument is required. The default is processing headers of any length.