Sky TechnologiesBook a discovery call
SKY TECHNOLOGIES / BLOG

Deliverability news.
Explained plainly.

Weekly posts on mailbox-provider rules, blocklists, authentication and sending infrastructure. Each one explains what changed, who it affects and what your team should check, with links to the original sources.

Read the latest post
HOW WE WRITE
PRIMARY SOURCES
PLAIN ENGLISH
WHAT TO CHECK

Every claim links to its source. No invented statistics. No inbox-placement guarantees.

LATEST POST1 POST · NEW POSTS WEEKLY
Industry update6 min readSpamhaus will enforce HELO, PTR and A-record checks from November 2026: what to check nowFrom November 2026, Spamhaus will gradually require a valid HELO, a PTR record and a matching A record for every sending IP. Here is what to check now.SpamhausReverse DNS (PTR)HELO / EHLOSending infrastructureRead the post
NEW TO DELIVERABILITY?

Start with the Signal Lab basics.

Six evergreen field guides explain the delivery path, SMTP replies, SPF, DKIM, DMARC and MX routing. They cover the background behind most blog posts.

Open Signal Lab
NEED A SECOND PAIR OF EYES?

Bring your setup.
We'll check the evidence.

If a new rule, a listing or a sudden drop in placement affects your sending, Sky can scope an evidence-led review. Your team keeps control of DNS, sending permissions and production changes.

Explore deliverability audit