Prolateral Consulting Ltd
Prolateral Consulting Ltd
SMTP SmartHost
Mail Relay
outgoing SMTP

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

Outgoing SMTP Email Services for Mail Server Administrators

outMail is an outgoing SMTP email relay service also known as "smart host" for use on your email servers.  outMail supports and works with the major email server solutions. Using outMail means you can continue to send emails hassle free with many more advantages than just using your Internet Service Providers server.

Send emails from your Internet connection using any email address or your domain name

Some Internet service providers will only let you send emails from their own email addresses or charge you a premium for using your own domain name.  With outMail you can send emails from your own domain name and other email address.  outMail also supports alternative TCPIP ports for SMTP (typically SMTP port 25) incase your ISP is blocking the port.

Avoid your emails being blacklisted

Some ISPs outgoing mail servers may become blacklisted.  We have a strict acceptable user policy and we constantly monitor our systems and third party blacklists to help ensure our servers remain unlisted.

Support for all SMTP Applications, servers and devices

  • Microsoft Windows Server - SMTP Server
  • Microsoft Exchange
  • Microsoft 365 Exchange
  • Unix Postfix
  • Unix SendMail
  • IBM Lotus Domino
  • Novell GroupWise
  • Mercury Mail
  • MDaemon
  • and many more.


  • Instant account creation - start sending emails instantly after signing up.
  • Send emails from any address - no limit on send from email addresses or domains.
  • Send emails from any location - ideal for home, office, and mobile users and devices.
  • Send emails from Microsoft 365 Exchange - configure the Office365 Exchange Send Connector to use outMail365.
  • Mail Relay Outbound Service - SMTP Authenticated Internet Mail Relay.
  • Standard SMTP ports - SMTP port 25 supported.
  • Alternative SMTP ports - additional SMTP TCP ports available to void your ISP blocking standard SMTP port.
  • Send by API - Send emails using a RESTful API as an alternative to SMTP.
  • SMTP Based Authentication - allows sending emails securely via authentication.
  • Security - support for SPF & DKIM.
  • Daily quota limits - based on package, but you can borrow quota to help with those mailshots.
  • Flexible quota burst - allowing for the days you need to exceed your quota (Quota explained here).
  • Reports - Online reports with exporting tools.


Choose the best package that suites your requirements.

Package Plan

Daily message limit

Cost per month


Outmail 10


£0.00 (FREE)

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Outmail 100



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Outmail 200



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Outmail 300



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Outmail 500



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Outmail 1000



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Outmail 2000



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Outmail 10000



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Prices exclude VAT


Complete how to guides with step-by-step instructions on how to configure your client mail application are here



 ApplicationKnowledge Base Article

MS Exchange 2000

Microsoft Exchange 2000 Setup guide

MS Exchange 2003

Microsoft Exchange 2003 Setup guide

MS Exchange 2007

Microsoft Exchange 2007 Setup guide

MS Exchange 2010

Microsoft Exchange 2010 Setup guide

MS Exchange 2013

Microsoft Exchange 2013 Setup guide

MS Exchange 2016

Microsoft Exchange 2016 Setup guide

MS Exchange 2019

Microsoft Exchange 2019 Setup guide

Microsoft 365 Exchange

Microsoft 365 Exchange Setup guide

Novell Groupwise

Novell GroupWise Setup guide


Postfix Setup guide

I'm very, very impressed with Prolateral's outgoing mail service!!  I had spent hours checking every setting I could think of to get my server to work with my ISPs mail relay, and no joy.

I then changed my SmartHost details in Exchange Server 2007 using the wizard from my ISP details to the details that you sent me for outMail and voila!! All our outbound emails were sent immediately. Brilliant.

David Lightfoot, South Shields, Tyne & Wear, UK