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Diffstat (limited to 'contrib/sendmail/doc/op/op.me')
-rw-r--r-- | contrib/sendmail/doc/op/op.me | 50 |
1 files changed, 47 insertions, 3 deletions
diff --git a/contrib/sendmail/doc/op/op.me b/contrib/sendmail/doc/op/op.me index 8d14002f0b65..6780db5dca5c 100644 --- a/contrib/sendmail/doc/op/op.me +++ b/contrib/sendmail/doc/op/op.me @@ -9,7 +9,7 @@ .\" the sendmail distribution. .\" .\" -.\" $Id: op.me,v 8.607 2002/05/22 19:58:33 gshapiro Exp $ +.\" $Id: op.me,v 8.609.2.2 2002/06/25 20:30:35 ca Exp $ .\" .\" eqn op.me | pic | troff -me .\" @@ -88,7 +88,7 @@ Sendmail, Inc. .de Ve Version \\$2 .. -.Ve $Revision: 8.607 $ +.Ve $Revision: 8.609.2.2 $ .rm Ve .sp For Sendmail Version 8.12 @@ -753,6 +753,12 @@ Notice: do not use the same key for .i sendmail invocations with different queue directories or different queue group declarations. +Access to shared memory is not controlled by locks, +i.e., there is a race condition when data in the shared memory is updated. +However, since operation of +.i sendmail +does not rely on the data in the shared memory, this does not negatively +influence the behavior. .sh 3 "/var/spool/clientmqueue" .pp The directory @@ -1274,6 +1280,13 @@ the flag .b \-bP can be used to print the number of entries in the queue(s), provided a process updates the data. +However, as explained earlier, the output might be slightly wrong, +since access to the shared memory is not locked. +For example, +``unknown number of entries'' +might be shown. +The internal counters are updated after each queue run +to the correct value again. .sh 3 "Forcing the queue" .pp .i Sendmail @@ -2769,6 +2782,34 @@ is still accepted. Notice that the MSP submits mail to the MTA via SMTP, and hence mail will be queued in the client queue in such a case. Therefore it is necessary to run the client mail queue periodically. +.sh 2 "Resource Limits" +.pp +.i Sendmail +has several parameters to control resource usage. +Besides those mentionted in the previous section, there are at least +.b MaxDaemonChildren , +.b ConnectionRateThrottle , +.b MaxQueueChildren , +and +.b MaxRunnersPerQueue . +The latter two limit the number of +.i sendmail +processes that operate on the queue. +These are discussed in the section +``Queue Group Declaration''. +The former two can be used to limit the number of incoming connections. +Their appropriate values depend on the host operating system and +the hardware, e.g., amount of memory. +In many situations it might be useful to set limits to prevent +to have too many +.i sendmail +processes, however, these limits can be abused to mount a +denial of service attack. +For example, if +.b MaxDaemonChildren=10 +then an attacker needs to open only 10 SMTP sessions to the server, +leave them idle for most of the time, +and no more connections will be accepted. .sh 2 "Delivery Mode" .pp There are a number of delivery modes that @@ -6557,6 +6598,7 @@ If not set, is either "CC f" if the option .b \-G is used or "c u" otherwise. +Note that only the the "CC", "c", "f", and "u" flags are checked. .ip DontBlameSendmail=\fIoption,option,...\fP [no short name] In order to avoid possible cracking attempts @@ -7050,6 +7092,7 @@ The characters ``@,;:\e()[]'' are always added to this list. .ip NiceQueueRun [no short name] The priority of queue runners (nice(3)). +This value must be greater or equal zero. .ip NoRecipientAction [no short name] The action to take when you receive a message that has no valid @@ -8674,6 +8717,7 @@ Fields are: Flags for this queue group. .ip Nice The nice(2) increment for the queue group. +This value must be greater or equal zero. .ip Interval The time between two queue runs. .ip Path @@ -10627,7 +10671,7 @@ replace it with a blank sheet for double-sided output. .\".sz 10 .\"Eric Allman .\".sp -.\"Version $Revision: 8.607 $ +.\"Version $Revision: 8.609.2.2 $ .\".ce 0 .bp 3 .ce |