Rackspace Email email authentication
Long-running hosted mailbox service.
SPF record
Add Rackspace Email to your domain's SPF record with this include:
include:emailsrvr.com
A complete record for a domain sending only through Rackspace Email:
v=spf1 include:emailsrvr.com ~all
What it costs you
1 of your 10 DNS lookups. That is the cheapest an include can be — the record it points at contains only IP ranges, with no further includes to follow. Behind it are 7 IP ranges.
Live record
This is what emailsrvr.com published when this page was generated:
v=spf1 ip4:108.166.43.0/24 ip4:146.20.86.8 ip4:146.20.161.0/25 ip4:161.47.34.7 ip4:173.203.187.0/25 ip4:184.106.54.0/25 ip4:204.232.172.40 ~all
DKIM
Enable DKIM inside Rackspace Email and publish the selector record it generates. DKIM matters more than SPF for deliverability, because a DKIM signature survives forwarding while SPF does not — see how selectors work.
DMARC
Neither SPF nor DKIM protects the address your recipients actually see until DMARC ties them
to it. Once Rackspace Email is authenticating, publish a DMARC record — start at
p=none with a reporting address and
tighten from there.
Check it worked
DNS changes take minutes to hours to propagate. Once published, run the domain through the checker — it resolves the full include chain and reports the real lookup count.