I checked with a mail admin friend of mine. According to him, sendmail is as you say. Exim, qmail, and postfix, on the other hand, support multiple <user>@ for multiple domains. Should we take a look at these three to see how they do it?
Matthew Schuyler Peck -----Original Message----- From: bill parducci [mailto:[EMAIL PROTECTED] Sent: Monday, March 10, 2003 9:01 AM To: James Users List Subject: Re: James for multiple domains Matthew Schuyler Peck wrote: > I've seen a repeated objection that no single solution has presented itself > as "the best". I submit that "the best" solution, for now, is the solution > that other mail servers use, since it works and is widespread and James > continues to lack its own solution to this important problem. Once this > solution has been identified (I admit, I have not examined > sendmail/qmail/exim/etc to figure out what, precisely, they do, but it > involves using the full email address as the mailbox identifier at some > level), all that remains is the time required to implement the solution. I > am happy to provide the time. I simply want an official solution. actually, sendmail does NOT use the 'full address' for processing mail. yes, you can tell sendmail that it represents multiple domains, however, processing beyond that is done solely upon the name of the recipient. this is why a server representing myfoo.com and mybar.com cannot have aliases of [EMAIL PROTECTED] and [EMAIL PROTECTED] sendmail will tell you that this is a duplicate entry. why? because domain validation is only done at the initial point of SMTP transaction (so that a reject can be issued prior to accepting data where unauthorized relays are attempted.). this is in contrast to james, which accepts all mail then determines propriety of addressing (*that* discussion you will find at least a few times on the list ! :o) i struggled with this problem as well some time ago and it seems that this behavior is due to the incestuous relationship between SMTP and DNS (tcp has nothing to do with the discussion other than the fact that the agreed upon port is 25 for SMTP and tcp was selected over udp for guaranteed delivery--contrasting dns which is just fine with udp). it seems that the guys who came up with the whole mail idea felt that it was best that the defacto naming system, dns, was better suited to being the keeper of machine/subdomain/domain identity and to limit mail systems to being only consumers of that information (which is why i think the currentl rbl solutions are so damn clever! :o) the caveat above was implemented because it became apparent that mail systems could be easily exploited to perform tasks outside of those desired by the owner. in other words, the only reason that mail systems consider domain at all is something of an afterthought. as the needs of users grew (and things like ISPs) showed up, there needed to be more add-ons to accommodate the multiple domains on a single server. sendmail addressed this via the use of virtualusertables (yes, that ugly 'virtual' word :o) the idea here was that you could create specific aliases that need not be defined as 'real' users by the host machine. last i checked, james had the same idea: http://james.apache.org/javadocs/org/apache/james/transport/mailets/JDBCVirt ualUserTable.html so to make a long story a little longer, i would say that james is really not different from other mailing systems in the way that it handles users/identities, it is really *when* it decides to do something about that information that makes it unique. that's how it looks in my little corner of the universe anyway... b --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
