Sendmail Installation and Operation Guide
SMM:08-69
MaxHeadersLength=N
[no short name] The maximum length of the sum of all headers. This can be used
to prevent a denial of service attack. The default is no limit.
MaxHopCount=N
[h] The maximum hop count. Messages that have been processed more than N
times are assumed to be in a loop and are rejected. Defaults to 25.
MaxMessageSize=N
[no short name] Specify the maximum message size to be advertised in the
ESMTP EHLO response. Messages larger than this will be rejected. If set to a
value greater than zero, that value will be listed in the SIZE response, otherwise
SIZE is advertised in the ESMTP EHLO response without a parameter.
MaxMimeHeaderLength=N[/M]
[no short name] Sets the maximum length of certain MIME header field values to
N characters. These MIME header fields are determined by being a member of
class {checkMIMETextHeaders}, which currently contains only the header Con-
tent-Description. For some of these headers which take parameters, the maximum
length of each parameter is set to M if specified. If /M is not specified, one half of
N will be used. By default, these values are 2048 and 1024, respectively. To
allow any length, a value of 0 can be specified.
MaxQueueChildren=N
[no short name] When set, this limits the number of concurrent queue runner pro-
cesses to N. This helps to control the amount of system resources used when pro-
cessing the queue. When there are multiple queue groups defined and the total
number of queue runners for these queue groups would exceed MaxQueueChil-
dren then the queue groups will not all run concurrently. That is, some portion of
the queue groups will run concurrently such that MaxQueueChildren will not be
exceeded, while the remaining queue groups will be run later (in round robin
order). See also MaxRunnersPerQueue and the section Queue Group Declara-
tion
. Notice: sendmail does not count individual queue runners, but only sets of
processes that act on a workgroup. Hence the actual number of queue runners
may be lower than the limit imposed by MaxQueueChildren. This discrepancy
can be large if some queue runners have to wait for a slow server and if short
intervals are used.
MaxQueueRunSize=N
[no short name] The maximum number of jobs that will be processed in a single
queue run. If not set, there is no limit on the size. If you have very large queues
or a very short queue run interval this could be unstable. However, since the first
N jobs in queue directory order are run (rather than the N highest priority jobs)
this should be set as high as possible to avoid "losing" jobs that happen to fall late
in the queue directory.
MaxRecipientsPerMessage=N
[no short name] The maximum number of recipients that will be accepted per
message in an SMTP transaction. Note: setting this too low can interfere with
sending mail from MUAs that use SMTP for initial submission. If not set, there is
no limit on the number of recipients per envelope.
MaxRunnersPerQueue=N
[no short name] This sets the default maximum number of queue runners for
queue groups. Up to N queue runners will work in parallel on a queue group's
messages. This is useful where the processing of a message in the queue might
delay the processing of subsequent messages. Such a delay may be the result of
non-erroneous situations such as a low bandwidth connection. May be overridden