sendmail, 4th Edition

Header Behavior in conf.c

The sendmail program has a built-in understanding of many header names. How those names are used is determined by a set of flags in the source file conf.c supplied with the source distribution. Site policy determines which flags are applied to which headers, but in general, conf.c applies them in the way that is best suited for almost all Internet sites. If you desire to redefine the flags for a particular header name, look for the name’s declaration in the C-language structure definition HdrInfo in conf.c. Be sure to read the comments in that file. Changes to header flags represent a permanent site policy change and should not be undertaken lightly. (We illustrate this process after explaining the flags.)

The flags that determine header use are listed in Table 25-4. Note that each flag name is prefixed with an H_.

Table 25-4. Header flags in conf.c

Flag	§	Versions	Description
H_ACHECK	H_ACHECK Header Flag (V5 and Later) on page 1139	V5 and later	Always process ?flags?.
H_BCC	H_BCC Header Flag (V8.7 and Later) on page 1140	V8.7 and later	Strip value from header.
H_BINDLATE	H_BINDLATE Header Flag (V8.10 and Later) on page 1140	V8.10 and later	Expand macros only at time of delivery.
H_CHECK	H_CHECK Header Flag (V5 and Later) on page 1140	V5 and later	Process ?flags?.
H_CTE	H_CTE Header Flag (V8.7 and Later) on page 1140	V8.7 and later	Is “content transfer encoding”.
H_CTYPE	H_CTYPE Header Flag (V8.7 and Later) on page 1140	V8.7 and ...