Many events can take a long time to complete—so long, in fact, that they can cause sendmail to appear to hang if they don’t time out. For example, when reading commands or data from a remote SMTP connection, the other side can be so slow that it becomes necessary for the local sendmail to time out and break the connection. Similarly, when reading from its standard input, sendmail might find that the program feeding it information is taking so long that a timeout becomes necessary.
The V8 version of the sendmail program has
introduced defaults for the amount of time it waits under various
circumstances. The forms of the
Timeout option are
O Timeout.keyword=value ← configuration file (V8.7 and later) -OTimeout.keyword=value ← command line (V8.7 and later) define(`conTO_keyword',` value') ← mc configuration (V8.7 and later) O Timeout=keyword=value,... ← configuration file (V8.6) -OTimeout=keyword=value,... ← command line (V8.6) define(`confREAD_TIMEOUT',``keyword=value,...'')← mc configuration (V8.6) Orkeyword=value,... ← configuration file (V8.1 through V8.5) -orkeyword=value,... ← command line (V8.1 through V8.5) Ortime ← configuration file (deprecated) -ortime← command line (deprecated)
Prior to V8 sendmail, only a single
time could be specified that set the
timeout for all SMTP transactions. Beginning with V8
sendmail, a list of
value pairs can be specified that set a
wide assortment of timeouts. In this section we focus ...