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Newsgroups: bit.listserv.banyan-l
Date:         Fri, 22 Jan 1993 09:21:24 CET
From:         frank=koperdraat@IC.UVA.NL
Subject:      re: Default forwarding in SMTP

> From:           Mike Wagner <mwagner@rosedale.org>
>
> We would like to set up our Banyan SMTP gateway to by default forward all
> outgoing messages to a specific address. Since the gateway doesn't
> understand MX records, and we would like to do some address munging on the
> way out to the Internet, this is our goal. Is there any mechanism to do
> this? We want ALL messages forwarded, even those destined for machines in
> the same TCP/IP domain as the gateway. Thanks for your input.

Hi Mike,

I don't know if the Banyan SMTP gateway does understand MX records. It will
however use a DNS (Domain Name Servers) to deliver a message directly. I
quote the SMTP release notes of version 1.20 (the same text appeared in the
release notice for version 1.14):

[ When you configure the SMTP service, you may specify a mail            ]
[ forwarding IP address.  This address is the IP address of the host     ]
[ to which your server forwards SMTP mail when no domain name server     ]
[ or default mail router is available.  The mail forwarding IP           ]
[ address is especially useful for the following reasons:                ]
[                                                                        ]
[       * If your server has no access to a domain name server or a      ]
[       default mail router, you can still forward SMTP mail through     ]
[       the host specified by the mail forwarding IP address.            ]
[                                                                        ]
[      *  If your server has access to a domain name server or a default ]
[       mail router, the host specified by the mail forwarding IP        ]
[       address can serve as a backup mail router.                       ]
[                                                                        ]
[ The SMTP service forwards a mail message to the host specified by      ]
[ the mail forwarding IP address only after attempts to resolve the      ]
[ SMTP mail address and to reach the default mail router fail.  A        ]
[ summary of the procedure that the SMTP service uses to forward SMTP    ]
[ mail follows:                                                          ]
[                                                                        ]
[ 1.  The SMTP service attempts to determine the IP address of a host    ]
[     specified by a hostname in the mail message.  The host can be      ]
[     either the mail message's destination or the next hop to which the ]
[     mail message must be forwarded.                                    ]
[                                                                        ]
[ 2.  If the attempt to resolve the IP address and hostname fails,       ]
[     the service tries to forward the mail message to the default mail  ]
[     router for delivery.                                               ]
[                                                                        ]
[ 3.  If the SMTP service cannot reach the default mail router, the      ]
[     service forwards the mail message to the host specified by the     ]
[     mail forwarding IP address, if one is configured.                  ]

What you want is use the 2nd or 3th option. This means you have to disable
the 1st option. To do this, you will have the remove al DNS specified in the
TCP/IP configuration of the server on wich the SMTP service is running.
This will also disable the 2nd option and leave only option 3, wich is
specified on an extra line (seventh line) in de SMTP configuration screen.

Hope this helps.
Frank Koperdraat
------------------------------------------------------
University of Amsterdam / IC   Email: frank@ic.uva.nl
Turfdraagsterpad 9             phone: +31-20-525 2387
NL-1012 XT  AMSTERDAM          fax  : +31-20-525 2084
Comments: Gated by NETNEWS@AUVM.AMERICAN.EDU