IGNORE_EMAIL_CASE

This configuration variable determines whether LISTSERV should treat email addresses with differently cased local parts as the same addresses in DBMS lists.

The default value is 0, which tells LISTSERV to operate per RFC821 and treat address fields with differently cased local parts as different addresses.

IGNORE_EMAIL_CASE=1 causes the ADD command to ignore the case of the local part of list subscriber entries. Although most modern mail clients are configured to ignore the case of the local part, this behavior technically violates RFC821, which states that local parts are considered case-sensitive.

If an entry whose local part differs only in case is found in the list during an ADD operation (for instance, JOE@EXAMPLE.COM vs. joe@EXAMPLE.COM), that entry will be assumed to be the entry that was sought, and the address field will be updated to the new case (that is, "JOE@" will be changed to "joe@"). No other change will be made to the entry unless there is a change in the name field, in which case the name field will also be updated.

Note the following caveats:

• Pre-existing duplicates are not automatically removed from lists when this option is set.
• Because ADD updates the case of entries, it is possible to end up with multiple entries that have exactly the same case.
• The only real way to de-dupe a given address is to DELETE and then re-ADD it.