Prolateral Consulting Ltd
Prolateral Consulting Ltd
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Prolateral offers primary and backup domain (DNS) services, with servers in key geographic locations providing the best service possible.


What are the limits for outMail?
What are the rate limits for outMail SMTP Mail Relay?


All outMail servers (SMTP SmartHost and Mail Relay) have the following restrictions and limits.

Maximum number of recipients is 200 per email. This exceeds the RFC2821 which defines the email protocol which recommends 100, and is best practice. Although outMail supports 200 recipients per email it is best practice to fine tune your email software to 100 or less as not all email clients conform fully to the RFCs

outMail permits up to 50 concurrent connections and up to 120 connections per minute. Each connection can be used to send multiple emails. These figures are needed for you email marketing software when setting rate limits for the outbound SMTP Server.

To protect the outMail servers and to enable fair usage there is a global quota restriction that prevents any outmail user from sending more than 10,000 messages per hour.  If the outMail package is greater than outMail10000 then please plan your email campaigns to take account of this restriction.

Each outMail service is also measured on a daily quota (Please see knowledgebase article on quota limits and max burst quotas).


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