SUMMARY: Controlled aliase access

Date: Mon Jan 25 1999 - 15:06:27 CST

Original question: Controlled access to an aliase?

How to limit the access to an email aliase? -- only letter that comes from an address on the aliase list is forwarded to each address on the list. All others are ignored or sent to a given address. I experienced this functionality i
n the past but do not know how to realize it now. Even the support engineer at SUN's tech support center can not do it.

Another common email aliase function: user may subscribe an email aliase by sending a letter to an aliase address. I guess the best way is, a daemon is fired by the arrival of the letter. User's address is then added to an aliase file. However, SUN en
gineer told me that the sendmail daemon takes care all the email related issues. Send mail does not send out or wake up user's code. Sendmail daemon can not be configured to achieve the fuction. But this is a common function and should have a solution.

Each of the following is a solution:
1. Install procmail or majordomo:
   Procmail from
   Majordomo from

2. read the man page on aliases - there is a description there on how to
   invoke a command when mail is sent to an alias (|). The input to the
   command is the email message itself. Warning - this can weaken your
   security, as anyone can send (almost) any input to your program.

3. Setup a dummy account whose user-id is the aliase-name(remove the original
   aliase). Write code to deal with letters sent to aliase-name@hostname. The
   code can be fired either by registrate it in .forward file under this
   user-id's home folder (similar to 2. above) or by registate the code as cron task.

Thanks to
Ian MacPhedran <>
David Evans <>
Sebastian Benoit <>
Kevin Sheehan <>
Al Hopper <>
Aki Sasaki <>
Charlie Mengler <>
Adams, Chad M CRL <>
Jeffrey C. Keyser <>
Ralph Finch <>
Jonathan Loh <>
Benjamin Cline <>

Yuming Huang

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