subdomain delegation for email routing

Fri Sep 26 19:00:20 PDT 2003

hi ya alan

On Fri, 26 Sep 2003, afactor wrote:

> Please let me clarify:
> 
> Management's stated desire is to reduce the load on the corporate email
> server which is currently straining under the virus/spam/worm
> load. Management feels strongly that email that is forwarded to the
> outside customer care vendor should not place a load on the corporate
> email server. 

see the postfix "big picture"
	- email comes in one end .. and email goes out the other end

> Management also feels that there should not be a delay in
> the delivery of said email (although arguably that delay may not be
> significant).

when receiving emails, your servers is always contacted before it
goes off to its merry way to its destination ( pop server )
	- even the firewall gets to redirect incoming emails

a very simple picture  of what happens first
	- dns checks where to deliver
	- mx checks if there is mx for the domains
	- helo/data process to the mail server defined
	- check for /etc/aliases and other mail config files
	- check for spam/antivirus stuff
	- deliver to local pop server
	- ...

	- and in your case ... dns server checking for subdomains
	-

- the mail has to be eceived and processed locally before it can be resent
  back out

	http://www.postfix.org/big-picture.html

> I believe that none of this mail is ever NOT forwarded although I can't
> say for certain whether the forwarding is done manually or not
> (incredibly I believe the forwarding of the email to the vendor may be a
> manually started batch job). The only requirement is that a copy of the
> email is saved/sent/forwarded to the primary company (for DR/backup
> reasons).

le'ts say this is requirement#1  "that a copy of the email is saved"

> Having said that I can't put an alias in the company's mail server as that
> doesn't meet the first requirement of eliminating delivery to the
> corporate email server.

let's say this is is requirement#2  "that it eliminated delivery to teh 
corp mail server"

requirement#1 and requirement#2 is contradictory
	you have to receive it someplace and than save a copy
	someplace else

best way to to eliminate human errors is let the machine do the forwarding

human errors being things like laziness, sick day, vacation, forgot,
fat fingers to delete, i'll reply to it instead of frowarding to
outsourced tech support, etc, etc

> And my second choice of setting up a second email
> server and delegating a zone to it (e.g., care.company1.com) was nixed as
> the company doesn't want to spend the capital.

its your option to implement what you want to see if it works ..

mine is simple /etc/mail/aliases  and /etc/mail/virtusertable
and other mail redirection and status and wizbang features
	- guarantee that the email is forwareded to outsourced-foo.com
	- keep a local copy
	- outsourced-food.com  provide reply "cc back to us" to customers
	email requests to get paid

==
== if email processing is already too slow ... adding dns processing
== will slow it down one more step ...
==

fun stuff..

c ya
alvin

> BTW, correct me if I am mistaken but I need to delegate a subdomain not
> because there are alot of users in the domain (actually there are just a
> handful of email addresses I need to handle) but because if I create and
> delegate a subdomain in DNS the mail delivered to these users will bypass
> the corporate mail server and go directly to the mail server configured in
> the NS server assigned to the new subdomain.
> 
> [Actually the above paragraph/question was what prompted me to send email
> to baylisa: I'd like verification that what I am thinking of doing will
> work as I imagine it will :)].
> 
> Unfortunately management prefers not to go this route. They do not have
> any qualms about delegating a newly created subdomain to the outside
> vendor just for the purpose of delivering this email. While the company is
> fairly large (national, retail, 100 stores, etc.) I don't believe they
> have configured any subdomains in their dns namespace.
> 
> So what about if the handful of email addresses are changed from
> customer-care-east at company1.com to customer-care-east at care.company1.com and
> instead of forwarding them to company1 at webvendor.com I create a  subdomain 
> and assign the NS record to webvendor.com:
> care.company1.com IN NS ns.webvendor.com
> 
> ... Assuming they correctly setup their dns server and mail server to
> accept email from care.company1.com.
> 
> --Alan
> 
> 
> 