subdomain delegation for email routing

[Chuck Yerkes]

Quoting Alan Factor (afactor at afactor.com):
> I have a client (company1.com) who has customers send email to several 
> special email accounts (such as customer service which goes to 
> care at company1.com). These emails are processed along with all other 
> corporate email by the corporate mail server and then forwarded to an 
> outside vendor (webservice.com) that handles these special email accounts. 
> A backup copy is made and kept by company1.com and the original is 
> forwarded to the vendor (e.g., to company1-cs at webvendor.com) and the vendor 
> responds to the email. Unfortunately average response times are 48 hours.

Well here's the problem.  I'd expect a typical 1-2 second lag
with the occasional couple hour lag on rare rare occasions.

I'd solve THIS problem - a series of aliases (or distribution
lists in LDAP, or the right TXT record in HESIOD (dns, really).
This is a 20 minute exercise on any Unix box running a real MTA.

> My client wants to have the customer service email delivered directly to 
> the outside vendor and I suggested that they create a subdomain 
> care.company1.com and delegate this subdomain to the vendor:

I don't think you can have an NS *and* an MX for the same item.
Pick one.

> care.company1.com IN  NS  ns.webservice.com
> care.company1.com IN  MX  mail.webservice.com
   (I'd put a number after that MX :)

> The vendor can forward email from care.company1.com to the appropriate end 
> user and then forward a backup copy to company1 (e.g., backup.company1.com)