Premium Relay

Premium SMTP relays for high deliverability

WHAT ARE THE MAIN ADVANTAGES OF USING PREMIUM RELAY?

  • Carefully vetted IPs with excellent reputation.
  • Ensure near 100% deliverability to all major providers and ESPs through Mailbux’s multi-relay system which resends hard rejects.
  • Powerful anti-spam and anti-virus outbound filtering to maintain IP reputation.

HOW DO I SIGN UP FOR PREMIUM RELAY?
Enterprise email – have Premium relay by default (free of charge).

ARE THERE ANY RESTRICTIONS ON THE USE OR SENDING LIMITS FOR PREMIUM RELAY?
Yes, to protect the infrastructure (from spammers, compromised users, runaway scripts, etc.) and to provide optimum service at all times.

Restrictions on use: Transmitting bulk emails or commercial emails including marketing emails and newsletters.

The system would issue a soft reject if over quota (on reaching bucket capacity), so any mails in queue would be accepted for delivery later. The leaky bucket does not delay messages that are accepted, even when reaching capacity, it only soft rejects the mail so that the client can automatically retry after some time.

Per-user buckets & their properties
  • Local mail → Capacity: 200 | Leak rate: 1 message every minute
  • External mail → Capacity: 50 | Leak rate: 1 message every 3.6 minutes
Recipients per-IP bucket & its properties
  • Recipients per sender-IP → Capacity: 500 | Leak rate: 1 message every minute

Each message can have up to a maximum of 50 recipients, please note that each recipient is counted as a single message towards quota calculation. That is, 50 messages to 1 recipient each are counted as 50 messages, while 1 message to 50 recipients is also counted as 50 messages.