Currently, we default to using the system-default sasl mechanisms list.  That list will include GSSAPI if the package is installed on the user's system.  But merely installing the GSSAPI package does not prepare qpidd to use GSSAPI.  The user must perform specific config steps to make it work.  And, since GSSAPI will be selected before other mechanisms, this means that many users will see qpidd fail as soon as they try  --auth=yes  .

It also seems dangerous to allow PLAIN, since users who install qpidd will then have an insecure system by default.

By accepting the system-default list we are allowing too many user-surprises.

The solution is to explicitly control the mech list, probably only allowing a single mechanism such as DIGEST-MD5, and give the user sufficient instruction on how to set up other mechanisms when they are desired.