Although all mail, under the hub scheme, should be passed to the hub for processing, certain errors should still be handled locally. By recognizing these errors locally, the user is advised of mistakes immediately, rather than having to wait for mail to bounce.
When we discussed delivery agents, we showed you that
Mlocal, P=/bin/mail, F=lsDFMAw5:/|@rmn, S=0, R=0, A=mail -d $u
, a specially defined delivery
agent exists. Called
For example, recall the earlier experiment with three demo rules:
S0 R@ one R@$+ two R$+@$+ three
When this rule set was given an address of
the missing user part), the RHS rewrote the workspace to be
Add the following new line to the client.cf file's rule set 0. Don't forget that the LHS, RHS, and comment must be separated from each other by tab characters, not spaces. But note that the RHS may contain space characters (not tabs) for clarity.
S0 # select delivery agent
Run sendmail again, this time to see which addresses are caught locally as errors and which are passed onward to the central hub.
@acme... Missing user name
Now feed sendmail a legal address:
This legal address, one with both a user and host part, bypasses the
error-handling rule and will be accepted for delivery via the