Dear Subscriber, Some days ago I sent a mail to list [log in to unmask] I have put the mail-option ACK 'on', as default. This has never produced the sending of an acknowledgement from a list-subscriber. But in this case, I received an acknowledgement from some hundred subscribers :( What is wrong? I think LISTSERV has to negate / delete the x-acknowledgement command in the header of the list. Yours, Fred Melssen listowner CPS-L and ETHNOHIS (at nic.SURFnet.nl)