On Mon, 3 May 2004 [log in to unmask] wrote:

>"LISTSERV list owners' forum" <[log in to unmask]> wrote on
>05/03/2004 01:39:41 PM:
>
>> Regarding Duplicate Messages - Does anyone know a good source for
>> sendmail admin or tell me how to delete timeout messages on sendmail
>> queue?
>
>This is kind of off topic for this list, but for sendmail, the most
>complete book out there is "sendmail" by Bryan Costales, with Eric Allman.
> Another good book is "sendmail Cookbook" by Craig Hunt.  Both are
>published by O'Rielly.  A third excellent book is "sendmail Performance
>Tuning" by Nick Christenson (Addison Wesley).

Another good source is simply doing a web search for "Sendmail" at Google.