Sendmail MAIL-HUB option

A mail hub is probably not what you w3ant since it specifies where incomming mail to the system will be sent to. There's two variations on sending outgoing mail to a remote mail server. One is to configure Sendmail with a smart host, which is where all non-local mail will be sent. The other is to configure a mail hub, which is where all mail will be sent. Mail hub is most often used in a null client configuration because Sendmail will never deliver anything locally in that case. I can't tell if "ALL outgoing mail" means that there will be no local mail delivery or not. You'll need to decide which you need to use.

To configure a smart host you need to include:

define(`SMART_HOST',`smtp.your.provider')

in the sendmail.mc you use to build sendmail.cf, replacing smtp.your.provider with the host name of the MTA that you want to send the mail to. Or, you can edit your sendmail.cf and set DS, like:

# "Smart" relay host (may be null)
DSsmtp.your.provider

To configure a mail hub you need to build a sendmail.cf using a sendmail.mc that contains:

divert(-1)
#
# Copyright (c) 1998-2000 Sendmail, Inc. and its suppliers.
#      All rights reserved.
# Copyright (c) 1983 Eric P. Allman.  All rights reserved.
# Copyright (c) 1988, 1993
#      The Regents of the University of California.  All rights reserved.
#
# By using this file, you agree to the terms and conditions set
# forth in the LICENSE file which can be found at the top level of
# the sendmail distribution.
#
#

#
#  This the prototype for a "null client" -- that is, a client that
#  does nothing except forward all mail to a mail hub.  IT IS NOT
#  USABLE AS IS!!!
#
#  To use this, you MUST use the nullclient feature with the name of
#  the mail hub as its argument.  You MUST also define an `OSTYPE' to
#  define the location of the queue directories and the like.
#

divert(0)dnl
VERSIONID(`$Id: clientproto.mc,v 8.16 2000/03/21 21:05:26 ca Exp $')

OSTYPE(unknown)
FEATURE(nullclient, smtp.your.provider)


editing the file to change "smtp.your.provider" and change "unknown" to one of:

aix3            aix4            aix5            altos  
amdahl-uts      a-ux            bsd4.3          bsd4.4  
bsdi1.0         bsdi2.0         bsdi            darwin  
dgux            domainos        dynix3.2        freebsd4  
freebsd5        gnu             hpux10          hpux11  
hpux9           irix4           irix5           irix6  
isc4.1          linux           maxion          mklinux  
mpeix           nextstep        openbsd         osf1  
powerux         ptx2            qnx             riscos4.5  
sco3.2          sco-uw-2.1      sinix           solaris2  
solaris2.ml     solaris2.pre5   solaris8        sunos3.5  
sunos4.1        svr4            ultrix4         unixware7  
uxpds

as appropriate. Then build a new sendmail.cf.

In either case you'll need to restart sendmail for the change to take effect.