Here's my take on what is going on. Since no one has access to really good information about the inner workings of Yahoo Groups and how the many different ISP's handle their mail we can only guess. My opinion is that this random inexplainable failure to deliver messages is directly related to the SPAM problem. Anyone running a mail service (ISP's) these days are forced to use some type of software SPAM control or run the risk of having their servers brought down by the volume of SPAM. These SPAM filters are varied and configurable many different ways. Most of them include a monitor of the sending domain and have triggers built in to auto-block a domain when large numbers of messages start coming in from that domain. This threshold will vary from ISP to ISP. Once the trigger fires, it can re-act many different ways. Considering that Yahoo Groups is large, and during a busy period might send out lots of email, I think they are triggering a SPAM response with some of the ISP's. The ISP may respond to the perceived SPAM attack by automaticly bouncing the message with an "unknown recipient" message. The intent is that the spammer will then drop that email address from their list and reduce the spam. Some ISP's then trigger a block of that domain. This can remain blocked until someone at the ISP manually releases the block, or they might configure to block for a period of time. This is only one of many scenarios that could cause this type of issue. There is not an easy solution to this problem. Spider Http://web.tampabay.rr.com -----Original Message----- From: 24hoursupport-bounce@xxxxxxxxxxxxx [mailto:24hoursupport-bounce@xxxxxxxxxxxxx] On Behalf Of Merin Sent: Saturday, September 27, 2003 1:05 AM To: 24hoursupport@xxxxxxxxxxxxx Subject: [24hoursupport] Re: bouncing emails Here's the thing, though...Yahoo has reported me as bouncing "unknown recipient" on several of my email accounts, all of which are completely valid and do not bounce from any other source. I really do think it's Yahoo being screwy rather than dozens of other mail servers. Merin http://www.goodcleansoap.com Selfishness is not living as one wishes to live, it is asking others to live as one wishes to live. --Oscar Wilde > Disagree with me if you wish. I was merely pointing out why it happens. > People's mailservers give incorrect responses and Yahoo! stops sending > mail. If I was sending several million someones a letter, and it was > returned as "unknown recipient," I wouldn't think "hmm, it just worked > yesterday," I would just stop sending them mail until they confirmed > that they mailing address was correct. It wouldn't be worth my effort > to do anything other than that. For a web-based membership management utility and information on list policies, please see http://nibec.com/24hoursupport/ To unsubscribe, send a blank email to 24hoursupport-request@xxxxxxxxxxxxx with "unsubscribe" (without quotes) in the subject.