Re: [cobalt-users] MX record question / Raq4i

[Jeff Lasman <jblists@xxxxxxxxxxxxx>]

flash22@xxxxxxx wrote:

> The www.domain.com entry seems to be a requirement of the way sendmail is
> configured on Raq's , it's a bit silly from an external point of view, but
> the machine needs it internally so it can authoratively handle the
> *@domain route properly

I have it on good authority that they did it so you could have
user@xxxxxxxxxxxxxxxxxxxx be completely separate from
user@xxxxxxxxxxxxxxxxxxxxxxxxxx  This was common years ago; hosting
companies offered sites at yourname.theirname.com for people who didn't
want to spend $100 for a two-year domain registration (which is what
Network Solutions once charged).  "www" in this regard, is simply
another "subdomain" in this example.  Why?  To make life easy.

> The authority document is RFC1033
> 
>   "MX records specify where mail for a domain name should be delivered."
> 
> Note that it says 'domain name' , not just 'domain', The RFC's tend to
> have very precise language, most of the time, usually, generally ;)
> 
> Other obscure trivia, for folks using CNAMES for web aliases
> 
> RFC974 requires resoloution of CNAMES *before* MX lookups (client)
> 
> Apparently, this was worded too obscurely, as
> RFC1480 went to the trouble to specificly prohibit MX -> CNAME-RR
> 
>   "It is not appropriate to ask to MX "your-host" to "path-host" (this
>    is sometimes called double MXing).  The host on the right hand side
>    of an MX entry must be a host on the Internet with an IP address"

Thanks for taking the trouble to document this; I didn't want to take
the time to look it up <smile>.

Jeff
-- 
Jeff Lasman <jblists@xxxxxxxxxxxxx>
Linux and Cobalt/Sun/RaQ Consulting
nobaloney.net
P. O. Box 52672, Riverside, CA  92517
voice: (909) 778-9980  *  fax: (702) 548-9484