mailcnfg(4) UNIX System V(Essential Utilities) mailcnfg(4)
NAME
mailcnfg - initialization information for mail and rmail
DESCRIPTION
The /etc/mail/mailcnfg file contains initialization information for the
mail and rmail commands. Each entry in mailcnfg consists of a line of
the form
Keyword = Value
Leading whitespace, whitespace surrounding the equal sign, and trailing
whitespace is ignored. Keyword may not contain embedded whitespace, but
whitespace may appear within Value. Undefined keywords or badly formed
entries are silently ignored.
Keyword Definitions
DEBUG Takes the same values as the -x invocation option of
mail. This provides a way of setting a system-wide
debug/tracing level. Typically DEBUG is set to a
value of 2, which provides minimal diagnostics useful
for debugging mail and rmail failures. The value of
the -x mail invocation option will override any
specification of DEBUG in mailcnfg.
CLUSTER To identify a closely coupled set of systems by one
name to all other systems, set Value to the cluster
name. This string is used to supply the ...remote
from... information on the From header line rather
than the system nodename returned by uname(2).
FAILSAFE In the event that the /var/mail directory is accessed
via RFS or NFS within a cluster (see CLUSTER above),
provisions must be made to allow for the directory
not being available when local mail is to be
delivered (remote system crash, RFS or NFS problems,
etc.). Value is a string that indicates where to
forward the current message for delivery. Typically
this is the remote system that actually owns
/var/mail. In this way, the message is queued for
delivery to that system when it becomes available.
For example, assume a cluster of systems (sysa, sysb,
sysc) where /var/mail is physically mounted on sysc
and made available to the other machines via RFS or
NFS. If sysc were to crash, the RFS/NFS-accessible
/var/mail would become unavailable and local
deliveries of mail would go to /var/mail on the local
system. When /var/mail is re-mounted via RFS/NFS, all
messages deposited in the local directory would be
hidden and essentially lost. To prevent this, if
FAILSAFE is defined in mailcnfg, mail and rmail check
for the existence of /var/mail/:saved, a required
subdirectory. If this subdirectory does not exist,
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mailcnfg(4) UNIX System V(Essential Utilities) mailcnfg(4)
mail assumes that the RFS/NFS-accessible /var/mail is
not available and invokes the failsafe mechanism of
automatically forwarding the message to Value. In
this example Value would be sysc!%n. The %n keyword
is expanded to be the recipient name [see mail(1) for
details] and thus the message would be forwarded to
sysc!recipient_name. Because sysc is not available,
the message remains on the local system until sysc is
available, and then sent there for delivery.
DELEMPTYMFILE If not specified, the default action of mail and
rmail is to delete empty mailfiles if the permissions
are 0660 and to retain empty mailfiles if the
permissions are anything else. If Value is yes,
empty mailfiles are always deleted, regardless of
file permissions. If Value is no, empty mailfiles
are never deleted.
DOMAIN This string is used to supply the system domain name
in place of the domain name returned by
getdomainame(3).
SMARTERHOST This string may be set to a smarter host which may be
referenced within the mail surrogate file via %X.
%mailsurr_keyword As described in mailsurr(4), certain pre-defined
single letter keywords are textually substituted in
surrogate command fields before they are executed.
While none of the predefined keywords may be changed
in meaning, new ones may be defined to provide a
shorthand notation for long strings (such as
/usr/lib/mail/surrcmd) which may appear repeatedly
within the mailsurr file. Upper case letters are
reserved for future use and will be ignored if
encountered here.
FILES
/etc/mail/mailcnfg
/etc/mail/mailsurr
/var/mail/:saved
/usr/lib/mail/surrcmd
SEE ALSO
mailsurr(4)
mail(1) in the User's Reference Manual
uname(2), getdomainame(3) in the Programmer's Reference Manual
NOTES
If /var/mail is accessed via RFS or NFS and the subdirectory
/var/mail/:saved is not removed from the local system, the FAILSAFE
mechanism will be subverted.
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