V configuration command was added to V8
sendmail to prevent old versions of
configuration files from breaking when used with V8
sendmail. The syntax for the
V configuration command looks like this:
Vlevel ← V8.1 through V8.5 Vlevel/vendor ← V8.6 and above
We describe the
vendor parts in the next two sections.
level is a positive integer. If
level is higher than the maximum allowed
for the current version, sendmail prints the
following warning and accepts the value:
Warning: .cf version level (lev) exceeds program functionality (max)
level is less than 0 or if the
V configuration command is omitted, the default
level is 0.
The effects of the various version levels are relatively minor. As sendmail continues to develop, they might become more pronounced. Currently, the version levels are as follows:
The check for a valid shell in /etc/shells is ignored (Section 10.8.3).
MX records are looked up with the RES_DEFNAMES and RES_DNSRCH cleared. The high bit is always stripped from the body of every mail message.
The sendmail program automatically adds a
-a. to the "
host" database map (Section 23.4.3) declaration, if that database map
isn’t declared in the configuration file.
RES_DEFNAMES and RES_DNSRCH are not turned off as they were for older
versions. Rule set 5 (Section 19.6) behavior is
UseErrorsTo option (UseErrorsTo) to true automatically. ...