The best way to do this is to write a script to add a '.IK SITE' line to
every list at the end of the header, and then create a SITE.KEYWORDS file
that says, for instance:

* Send= *@EXAMPLE.COM

This will work in almost all cases. The exceptions I can think of are:

- You did not specify a "Send=" keyword in your list. Before the change, you
had the default "Send= Public" behaviour, whereas after the change only
*@EXAMPLE.COM can post. This is unlikely since "Send=" is in every template
and always one of the key things to think about when creating a new list, so
I would expect missing "Send=" keyword to be mistakes made when creating the
list, not design decisions.

- The list is moderated, although this depends on what your requirement is
for that scenario. Anyway, if the list was moderated before the change, it
will still be moderated after the change and that will include postings from
*@EXAMPLE.COM.

- There may be other settings in the list that block accesses from
EXAMPLE.COM or one of its sub-domains, and you will have to deal with these
on a case by case basis. But I guess that would not be a problem, if someone
explicitly blocked a particular domain, there would have to be a reason.

Scripts to change all lists follow the following general design:

1. Stop LISTSERV.

2. Make a copy of *.list before you run the script. Just in case...

3. The script must go over *.list and, for each list, execute 'listview xxx
> tempfile' to convert the list to a text file. You then make whatever
changes you wish to the text file, and copy it over to the original
xxx.list. Make sure to only modify the header lines. The recipient lines are
encoded and you should probably leave them alone. It is safe to delete one
recipient line, but editing recipient lines is delicate, do at your own
risk, etc.

4. Restart LISTSERV. You will get copious warnings about lists not being in
the right format, but LISTSERV can import a list from a text file and does
so automatically.

The key is that you cannot do any of that while LISTSERV is running. This
feature was developed to migrate between different operating systems (every
system has some kind of text file format, so we just needed export and
import tools). 'listview' is the export tool for Windows and unix, and the
import tool is built into LISTSERV.

  Eric