We are mass blocking Probe and spam IP addresses
HJRP Mail enforces sender infrastructure standards at SMTP time to protect recipients from spam. These checks apply to every sender, no exceptions.
Your sending IP must have a PTR record, and that PTR record's hostname must resolve forward (A/AAAA) back to the same IP.
Most spam and botnet traffic comes from IPs with no PTR record, or a mismatched one. This check alone filters the vast majority of it before anything else is inspected.
Rejections you may see:
"No confirmed PTR record" — no PTR exists for your IP
"Couldn't find your hostname" — PTR exists but forward lookup fails or doesn't match
Fix: Set a PTR record with your provider, and make sure the hostname it points to resolves back to the same IP.
Sending IPs are checked against blocklists. An IP with an active blocklist listing will be rejected regardless of other checks passing.
Additionally, HJRP maintains it's own blocklist (550 5.7.501) that we've kept from our last mail service.
Fix: Identify which list you're on and follow its delisting process. Delisting is outside HJRP's control — it's between you and the list operator.
Every IP without certification starts with a low or neutral reputation and earns trust over time based on sending behavior.
Reputation is global across the HJRP ecosystem — bad behavior against one domain or recipient class affects deliverability everywhere on HJRP Mail.
It's continuously evaluated, not a one-time check. Sustained complaints or abuse patterns will drop a previously fine score.
Once a score crosses the rejection threshold, mail is rejected at SMTP time (550 5.7.504 — sender reputation too low).
Probes and scanners with no real sending history are scored the same as any unfamiliar IP.
DKIM may be required for reliable delivery. While not always a hard SMTP-time gate, mail without valid DKIM signing is at higher risk of rejection or being treated as lower-trust, particularly as reputation scoring weighs it more heavily.
Fix: Configure DKIM signing on your outbound mail server and publish the corresponding DNS record.
5. HELO
Your HELO must be a FQDN (Fully-qualified Domain Name). If you don't have a FQDN as your HELO, You may be rejected for "HELO must be FQDN"
Many probe and spam servers do not use this, So this will block a big amount of spam.
You must comply with these requirements to send to HJRP Mail users (paid and free)