subdomain delegation for email routing

Fri Sep 26 18:36:55 PDT 2003

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

They don't want to be responsible for anything that goes wrong.

> 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).

With the delegation, you will have zero control over getting any copies.
The emails never touch your network.  You will rely 100% on the other
company, for proper backups of all messages.

>
> 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. 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.
>
> 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.

You really do not have to "delegate" the subdomain.  This has an additional
issue of giving over control of a piece of your namespace to another
authority.  Hence the term "delegate".

All you need to do is create an MX record in your domain.
care    IN   MX  10 mail.webcompany.com.

That is all.  With that one entry all mail addressed as
joeblow at care.company1.com will be delivered to mail.webcompany.com.

> [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.

We here at Seagate (My group maintain Seagate's
firewalls/SMTP(sendmail)/DNS services) do not delegate any subdomains
outside our company.  We maintain the records ourselves.

>
> 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.

This is usually a big assumption.

>
> --Alan

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