HP-UX Mailing Services Administrator's Guide

Configuring and Administering Sendmail
Creating Sendmail Aliases
Chapter 264
chess_club: [e-mail], marie@buffalo,
bigvax!amlabs!denise, [e-mail]
owner-chess_club: [e-mail]
Any errors that Sendmail encounters while trying to deliver mail to the
members of the chess_club mailing list would be reported to mike.
Avoiding Alias Loops
You must avoid creating aliasing loops. Loops can occur either locally or
remotely. An example of a local alias loop is as follows:
#Example of a local alias loop
first : second
second : first
While regenerating the alias database, the newaliases command does
not notice a loop like the one shown in the previous example. However,
after the alias database is generated, mail addressed to either first or
second is not sent. If the recipients for the message are only in the local
alias loops, the message is returned with the error message All
recipients suppressed.
In the previous example, if mail is addressed to first, first expands to
second, which expands back to first. This causes Sendmail to remove
first from the recipient list as a duplicate.
# Example alias entry on host sage
dave : dave@basil
# Example alias entry on host basil
dave : dave@sage
The following is an example of a remote aliasing loop:
Mail sent to dave at either host sage or host basil bounces between the
two systems. Sendmail adds a tracing header line (Received:) with each
hop. When 26 tracing header lines have been added, Sendmail recognizes
the aliasing loop and aborts the delivery with an error message.