>IP authentication has a serious drawback: it only works for mail you know >is coming, from some the mail server administrator has approved. Great >for in-house mail systems but limited usefulness elsewhere. I've seen >systems by which clients can approve mail, but mostclients don't know >enough to take the steps.
Not entirely true. Where it is limited is in the fact that you have to know the IP of the person trying to connect to the mail server to relay. But from an ISP standpoint, this is easy. A given ISP knows in advance what their range of IPs are that they assign to their customers. They have to know them, they assign them. So all they have to do is put the list of IPs they assign to their customers into their IP list for the mail server, and anyone connected to that IP will have access to relay thru the mail server. But, like I said, for many of the smaller ISPs this can't safely be used. Sure, they know the range of IPs that their customers may have, but that range is granted via whoever the larger ISP is that they subcontract to. And for some, the IPs may be used among multiple subcontract small ISPs. So they won't know if the person connecting is really one of their customers, or a customer from some other ISP that happens to also contract thru the same larger ISP. An example of this is PSINet's dialup services. They don't actually run their own dialup service. They (used to?) contract to Earthlink for dialup. They happened to use IP Authentication for their services (mail and news). That meant that all PSINet customers had transparent access to the mail and news servers... but so did all Earthlink customers. >You may want to download and evaluate 4D Web Mail Lite from www.4d.com. >Just for contrast. Nah... I'm a very happy SIMS user. In fact, if you want POP Authentication, you may want to look into SIMS from Stalker (www.stalker.com). Its 100% free, supports IP Authentication, SMTP Authentication, and POP Authentication. As well as static blacklists, RBLs, and a few other server side anti-spam hooks. Its actually a very nice product, and runs great on 030's and up. -chris <http://www.mythtech.net> ___________________________________________________________________________ To unsubscribe send a mail message with a SUBJECT line of "unsubscribe" to <[EMAIL PROTECTED]> or <[EMAIL PROTECTED]>
