Platforms

All


Abstract

This variable sets the default for the Loopcheck= keyword for all lists on the server.


Examples

z/VM:

DEFAULT_LOOPCHECK = 'FULL'

Unix:

DEFAULT_LOOPCHECK="FULL"

export DEFAULT_LOOPCHECK

Windows:

DEFAULT_LOOPCHECK=FULL


Details

LISTSERV's loopcheck heuristic defaults to "Loopcheck= Normal" if there is no explicit "Loopcheck=" setting in the list header. 

Background:  This is a backward-compatible change that eliminated from the default test suite the test that results in the error "Sender:", "From:" or "Reply-To:" field pointing to the list. 

This test was eliminated because the kinds of loops it was designed to prevent no longer occur on a typical discussion list; most MTAs that were responsible for them have long since been fixed. On the other hand, there are still exceptions, and this test remains the only reliable way to catch these kinds of loops. To put things in perspective, whenever you post something to a discussion list and you, the poster, receive a notice that the mailbox does not exist, it is a signal that the list may be at risk for this type of loop. Nowadays, this almost never happens, but there are still lists where it does. In addition, the larger the list, the higher the risk.

To revert to the older  behavior at the server level, set DEFAULT_LOOPCHECK=FULL as shown in the examples above.  This setting may then be overridden at the list level if desired.

In the future, it is anticipated that other tests found to be obsolete will be moved from the "Normal" suite to the "Full" suite, for the same backward compatibility.


Default Value

NORMAL