SMM:08-66
Sendmail Installation and Operation Guide
DontExpandCnames
[no short name] The standards say that all host addresses used in a mail message
must be fully canonical. For example, if your host is named "Cruft.Foo.ORG"
and also has an alias of "FTP.Foo.ORG", the former name must be used at all
times. This is enforced during host name canonification ($[ ... $] lookups). If this
option is set, the protocols are ignored and the "wrong" thing is done. However,
the IETF is moving toward changing this standard, so the behavior may become
acceptable. Please note that hosts downstream may still rewrite the address to be
the true canonical name however.
DontInitGroups [no short name] If set, sendmail will avoid using the initgroups(3) call. If you are
running NIS, this causes a sequential scan of the groups.byname map, which can
cause your NIS server to be badly overloaded in a large domain. The cost of this
is that the only group found for users will be their primary group (the one in the
password file), which will make file access permissions somewhat more restric-
tive. Has no effect on systems that don't hav e group lists.
DontProbeInterfaces
[no short name] Sendmail normally finds the names of all interfaces active on
your machine when it starts up and adds their name to the $=w class of known
host aliases. If you have a large number of virtual interfaces or if your DNS
inverse lookups are slow this can be time consuming. This option turns off that
probing. However, you will need to be certain to include all variant names in the
$=w
class by some other mechanism. If set to loopback, loopback interfaces
(e.g., lo0) will not be probed.
DontPruneRoutes [R] Normally, sendmail tries to eliminate any unnecessary explicit routes when
sending an error message (as discussed in RFC 1123 § 5.2.6). For example, when
sending an error message to
<@known1,@known2,@known3:user@unknown>
sendmail will strip off the "@known1,@known2" in order to make the route as
direct as possible. However, if the R option is set, this will be disabled, and the
mail will be sent to the first address in the route, even if later addresses are known.
This may be useful if you are caught behind a firewall.
DoubleBounceAddress=error-address
[no short name] If an error occurs when sending an error message, send the error
report (termed a "double bounce" because it is an error "bounce" that occurs
when trying to send another error "bounce") to the indicated address. The address
is macro expanded at the time of delivery. If not set, defaults to "postmaster". If
set to an empty string, double bounces are dropped.
EightBitMode=action
[8] Set handling of eight-bit data. There are two kinds of eight-bit data: that
declared as such using the BODY=8BITMIME ESMTP declaration or the
-B8BITMIME
command line flag, and undeclared 8-bit data, that is, input that
just happens to be eight bits. There are three basic operations that can happen:
undeclared 8-bit data can be automatically converted to 8BITMIME, undeclared
8-bit data can be passed as-is without conversion to MIME (``just send 8''), and
declared 8-bit data can be converted to 7-bits for transmission to a non-8BIT-
MIME mailer. The possible actions are:
s
Reject undeclared 8-bit data (``strict'')
m Convert undeclared 8-bit data to MIME (``mime'')
p
Pass undeclared 8-bit data (``pass'')
In all cases properly declared 8BITMIME data will be converted to 7BIT as