Complex Actions Made Simple
Beginning with V8.7 sendmail, rule-testing mode offers six simple commands that accomplish complex tasks. They are listed in Table 8-1.
Command |
Version |
§ |
Description |
|
V8.7 and above |
Canonify a host | |
|
V8.7 and above |
Look up MX records | |
|
V8.7 and above |
Look up a database item | |
|
V8.7 and above |
Select whom to /parse or /try | |
|
V8.7 and above |
Parse an address | |
|
V8.7 and above |
Try a delivery agent |
A lone /
character will cause the following usage
message to print:
Usage: /[canon|map|mx|parse|try|tryflags]
Anything other than the commands shown in Table 8-1 (such as /foo
) will produce
an error:
Unknown "/" command /foo
Canonify a Host with /canon
The
/canon
rule-testing command causes
sendmail to look up the canonical (official,
fully qualified) name of a host and print the result. The form for
this command looks like this:
/canon host
If host is missing, the following usage message is printed:
Usage: /canon address
When you correctly supply the hostname as the argument, sendmail looks up the canonical name and returns the result:
> /canon icsic
getcanonname(icsic) returns icsic.icsi.berkeley.edu
>
Here, the hostname icsic
was looked up. Because
its canonical name was found, that name is printed following the
returns
. If the hostname had not been found,
sendmail would have printed that same name ...
Get Sendmail, 3rd Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.