Name
DialDelay
Synopsis
Many Internet providers allow small sites (such as home machines) to
dial up when there is a demand for network traffic to flow. Such
connections are usually of short duration and use the PPP or SL/IP
protocols. A problem can arise when this dial-up-on-demand is
instigated by sendmail.[22] The process of negotiating a dial-up
connection can take so long that sendmail will
have its attempt to connect(2) fail. (See also
the connect
keyword for the
Timeout
option in See this section).
To remedy this situation, V8.7 and later offer the
DialDelay
option. It is declared like this:
O DialDelay=delay ← configuration file (V8.7 and later) -ODialDelay=delay ← command line (V8.7 and later) define(`confDIAL_DELAY',delay)← mc configuration (V8.7 and later)
The argument delay
is of type
time. If this option is entirely omitted or if
delay
is omitted, the default is then zero
and no delay is enabled. The default for the mc
configuration technique is also zero. If the unit of time is omitted
from the time declaration, the default is seconds.
If delay
is nonzero and
sendmail has its initial
connect(2) fail, it will
sleep(3) for delay
seconds and then try to connect(2) again. Note
that sendmail tries to connect again only once,
so the delay
should be large enough to
accommodate your anticipated worst-case delay. On the other hand,
care should be taken to avoid excessively long delays that can make
sendmail appear to hang. No check is made by
sendmail for absurdly large values ...
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