jessea@dynasys.UUCP (Jesse W. Asher) (03/06/90)
I recently posted an article asking why I couldn't use domains without
registering. The more I find out about this, the less convinced I am
of the greatness of domains. Question: Why in the world would I want
to have mail sent to another site just so that site could send it to
me? If, for example, my domain is "dynasys.com", what is the advantage
of having my mail sent to the entity that takes care of the "com" domain
only to then be sent to me? Especially when we have smart mailers that
will route the stuff directly to me. After reading the RFC and asking
all these questions, domains do not seem to be the great thing that many
are making them out to be. Comments?
--
Jesse W. Asher - Dynasys - (901)382-1705 Evening: (901)382-1609
6196-1 Macon Rd., Suite 200, Memphis, TN 38134
UUCP: {uunet,fedeva,rayo}!dynasys!jesseackd@bu-pub.bu.edu (Christopher Davis) (03/06/90)
>>>>> On 6 Mar 90 02:01:11 GMT, jessea@dynasys.UUCP (Jesse W. Asher) said: > [...] The more I find out about this, the less convinced I am of the > greatness of domains. Question: Why in the world would I want to have > mail sent to another site just so that site could send it to me? > If, for example, my domain is "dynasys.com", what is the advantage of > having my mail sent to the entity that takes care of the "com" domain > only to then be sent to me? Especially when we have smart mailers that > will route the stuff directly to me. After reading the RFC and asking > all these questions, domains do not seem to be the great thing that many > are making them out to be. Comments? This seems to be a misinterpretation of how the DNS MX record is handled. The advantage here is that sites using DNS (we will, for the moment, ignore UUCP pathalias/comp.mail.maps style routing) do a lookup, get an MX, then send the mail *over the Internet* to that MX. Example: Bill Well's machine, twwells.com: Script started on Tue Mar 6 06:38:59 1990 6:39am ckd@bass : ~ % nslookup Default Server: BU-PUB.BU.EDU Address: 128.197.21.21 [...] > twwells.com Server: uunet.uu.net Address: 192.48.96.2 twwells.com origin = uunet.UU.NET mail addr = postmaster.uunet.UU.NET serial=900228, refresh=432000, retry=3600, expire=864000, min=172800 twwells.com server name = uunet.UU.NET twwells.com server name = seismo.CSS.GOV twwells.com preference = 200, mail exchanger = uunet.uu.net uunet.UU.NET inet address = 192.48.96.2 uunet.UU.NET inet address = 137.39.1.2 seismo.CSS.GOV inet address = 192.12.141.25 [...] script done on Tue Mar 6 06:39:51 1990 The magic part is the line reading: twwells.com preference = 200, mail exchanger = uunet.uu.net which means that my mailer will send mail for user@twwells.com to uunet.uu.net through the Internet, and uunet can then arrange to get it to you. Otherwise, I might have to use twwells!user@uunet.uu.net, or user%twwells.uucp@uunet.uu.net, or other strange and arcane mutterings, just to get mail through to you. Mail does not go to "the entity that takes care of the 'com' domain" (namely nic.ddn.mil)--they just register your domain so nobody else gets it. (Imagine if Boston U, Brown U, and Bucknell U all used "bu.edu"...) Naturally, NONE of this applies outside the DNS (in particular, none of this applies to sites using comp.mail.maps for routing). -- Christopher Davis, BU SMG '90 <ckd@bu-pub.bu.edu> <smghy6c@buacca.bitnet> "Basic upshot - get your science straight, or start getting used to the taste of your Nikes." --Siobahn Morgan, thebang@blake.acs.washington.edu
roy@phri.nyu.edu (Roy Smith) (03/06/90)
In article <75@dynasys.UUCP> jessea@dynasys.UUCP (Jesse W. Asher) writes: > Question: Why in the world would I want to have mail sent to another > site just so that site could send it to me? If, for example, my domain > is "dynasys.com", what is the advantage of having my mail sent to the > entity that takes care of the "com" domain only to then be sent to me? One common confusion (and I admit, I was confused by this myself) is that domain names, IP addresses, and mail paths are all, at least in the general sense, orthagonal concepts. There is no reason why, just because you are a top-level .com domain that the .com nameserver has to have anything to do with your mail other than handing out your nameserver resource records (RRs) to anybody who asks for them. Imagine the following. I've got a bunch of machines with names of xx.phri.nyu.edu. They all happen to be on the same ethernet, with IP addresses of 128.122.136.xx, but that doesn't mean anything. In fact, there is a machine on my ethernet with a 128.122.136.xx which isn't in the phri.nyu.edu domain. Now, let's say I set up a machine at home. It's owned by phri, and used for phri business, so we decide it should have a phri name. We call it foo.phri.nyu.edu. It's not on the Internet, but does have a uucp link to phrivax.phri.nyu.edu. We just have to install an MX record saying that phrivax.phri.nyu.edu is where you should send mail for foo.phri.nyu.edu. Now, lets say that the phone call involved in that would be long distance and I'd rather not pay those bills, and there just happens to be a site on the Internet, say bozo.com, down the street from me that is willing to set up a uucp link to me and be my mail exchanger. Fine, we take out the MX record described earlier and put in one saying that bozo.com is now the mail exchanger for foo.phri.nyu.edu. -- Roy Smith, Public Health Research Institute 455 First Avenue, New York, NY 10016 roy@alanine.phri.nyu.edu -OR- {att,philabs,cmcl2,rutgers,hombre}!phri!roy "My karma ran over my dogma"
lyndon@cs.AthabascaU.CA (Lyndon Nerenberg) (03/07/90)
In article <75@dynasys.UUCP> jessea@dynasys.UUCP (Jesse W. Asher) writes: >Question: Why in the world would I want >to have mail sent to another site just so that site could send it to >me? If, for example, my domain is "dynasys.com", what is the advantage >of having my mail sent to the entity that takes care of the "com" domain >only to then be sent to me? That's not what happens. If the site is an internet site, and you have an internet forwarder, mail for your domain originating at an internet site will go directly to your forwarder (one hop in most cases) who will forward it (via uucp presumably) to your domain gateway. For example, .AthabascaU.CA is not connected to the internet. Our internet forwarder is decwrl.dec.com. They advertise an MX record for our domain, so any internet mail is sent there. Our gateway polls them to pick up our mail. I would guess our average hop count for mail from internet sites is around 2.5 by the time it gets to decwrl. For uucp sites running pathalias and a smart router, they will pick up a route to your domain via the map data. Again, an example. Our uucp fateway for AthabascaU.CA is a machine known as atha. If your routing database is set up properly, any mail you send to foo.athabascau.ca will route ...!atha!foo.athabascau.ca. Bitnet has similar provisions for gatewaying, as does CDNnet and most (but not all) other "networks." If a host is on both the Internet and the UUCP network, it's their decision as to which routing match takes precedence. Most favour the internet, since it provides much faster delivery to the end point (gateway) machine. -- Lyndon Nerenberg VE6BBM / Computing Services / Athabasca University {alberta,decwrl}!atha!lyndon || lyndon@cs.AthabascaU.CA UREP: Peru in disguise?