Header limit MTA option

Message size MTA options:  (integer)
The  option sets a limit, in MTA blocks (see the    MTA option), on how big a message&#x27;s primary (outermost) header can be. Headers over the specified size will be (silently) truncated. The default is 2000 blocks.

Source channels may have their own, more restrictive,  set; each channel will minimize its own setting  with this general, MTA-wide   setting.

Compare with the   and   MTA options, which instead of silent truncation in the form of deletion of the header lines, cause silent "truncation" by forcing the excess header material into the message body. And see also the  channel option, limiting how much of the header the MTA will process. And for yet more approaches to header limits and header truncation, see the   and   channel options, and the ,  , and    header trimming options.

See also:
 * Message size MTA options
 * block_size MTA Option
 * max_header_lines MTA Option
 * max_header_blocks MTA Option
 * maxprocchars Option
 * maxheaderaddrs Option
 * maxheaderchars Option
 * headertrim Option
 * headerlimit Option