There are a few steps to setting up IP address isolation.
Delegate Authority
If you don't have control of the sender domain it's best to have
authority delegated for a subdomain of your choosing e.g.
email.domain.com. For this example the records the domain
administrator would need to action are as follows. The marketing
team will no doubt have input to the actual subdomain, but email is
a common choice.
Domain|Type|Answer
email.domain.com|SOA|ns1.email.domain.com abuse@email.domain.com
email.domain.com|NS|ns1.email.domain.com
email.domain.com|NS|ns2.email.domain.com
ns1.email.domain.com |A|123.108.147.10
ns2.email.domain.com|A|123.108.148.10
MX, A and TXT
There are separate MX records for in and out bound
addresses:
email.domain.com|MX|smtp1.email.domain.com. [Preference =
10]
email.domain.com|MX|smtp10.email.domain.com. [Preference =
20]
smtp1.email.domain.com|A|123.108.144.5
smtp10.email.domain.com|A|123.108.149.134
The SPF record authorizes the hosts that are allowed to use this
domain name so that a receiving host may check authorization,
thereby preventing domain spoofing:
email.domain.com|TXT|"v=spf1
ip4:123.108.149.0/24 ~all"
The SPF record should be created
for the domain in the From address. Here's a handy tool to create
new records:
http://www.microsoft.com/mscorp/safety/content/technologies/senderid/wizard/
The subdomain will also be used
for tracking, online version and preference centre, so A records
also should be created:
links.email.domain.com|A|123.108.151.102
Additional Questions
Questions to ask regarding
previous email marketing activity
- What was the email volume per campaign?
- What was the campaign frequency?
- What was the date of the last campaign?
- What was the sender IP address of previous campaigns?
- What was the unsubscribe URL for previous campaigns
- Can we have a sample from a previously deployed campaign - or
new creative if available?
- What was the bounce rate of previous campaigns?
- What was the bounce policy?
- Moving forward will we host a preference centre/unsubscribe
page or will this be external? If external check that it isn't
password protected as this is contrary to CAN-SPAM.
Finally a breakdown of recipient
domains will highlight any mitigating steps to take with specific
ISP's.
Domain Key
Domain Keys are an authentication mechanism to verify mail
claiming to come from a given domain. Domain Keys
use SHA256/SHA2 - Secure Hash Algorythm. SHA2 is designed to
be infeasible to produce a message (e.g. a password) from
a given digest (e.g. a hashed password).
