How to Configure Microsoft Exchange to use
the Arrowmail Smarthosts

Arrowmail has 3 separate smarthost mail-servers and, luckily, Exchange 2003, 2007 and 2010 know how to make use of multiple smarthosts for redundancy and load-balancing.
This means that if one of our smarthosts is very busy, has failed or is undergoing maintenance, your Exchange server can continue to send out emails, uninterrupted.

In Exchange 2003, it's possible to configure a smarthost on the Default SMTP Virtual Server but, if you do it this way, you can only set a single smarthost.
The preferred method, therefore, is to use an SMTP Connector for your outgoing emails which does allow multiple smarthosts to be specified.

For Exchange 2007/2010 there's only one way to configure a smarthost which is on the Send Connector.

For simplicity, the instructions on this page assume that you only have one Exchange server in your organisation.
If you have multiple Exchange servers, there are a few minor differences which we'll be happy to advise you about.

How To Configure a Smarthost on Exchange 2003

Open Exchange System Manager and click on the + next to Connectors to see if you are already using an SMTP Connector.
SBS2003 comes with a pre-configured SMTP Connector as shown below:-

If you need to create a new connector:-
Right-click on Connectors and select New - SMTP Connector...

If a SMTP Connector already exists, right-click on it and choose Properties

The SMTP Connector - Properties page opens which has 8 tabs.
(There could be a 9th tab called Security if you've previously enabled this tab by a registry change, but, in any case, there's nothing to configure on this tab.)

We'll start on the General tab where there are 3 things to configure:-

Go to the Address Space tab.
Click Add... and select the default options which are:-
Type = SMTP
Email Domain = *
Cost = 1
Connector scope = Entire Organisation
"Allow messages to be relayed to these domains" is not selected

Go to the Advanced tab.
Click on Outbound Security...
Select Basic authentication (password is sent in clear text) and then Modify...
Enter your username and password for the Arrowmail Smarthosts.

If you would like all messages, sent from your server to our smarthosts, to be encrypted then select TLS encryption:-

There's nothing to change on the other 5 tabs, but we've shown what they should look like, anyway, so you can check that nothing's been changed.

The Connected Routing Groups tab:-

The Delivery Restrictions tab:-

The Content Restrictions tab:-

The Delivery Options tab:-

...and finally, the Details tab:-

Click OK and close Exchange System Manager.

In order for the new settings to take effect, you need to restart the following services:-
Microsoft Exchange Routing Engine and
Simple Mail Transport Protocol (SMTP).

Rebooting the server will also enable the new settings, if this is easier.

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How To Configure a Smarthost on Exchange 2007 and Exchange 2010

If your Exchange Server 2007/2010 is currently able to send emails externally, a Send Connector must already have been created and configured correctly on the Hub Transport server.
Configuring Exchange 2007/2010 to use the Arrowmail Smarthosts, therefore, just requires you to modify the settings on this Send Connector.

For Exchange 2007/2010, Microsoft has split up into separate roles, the various jobs that Exchange has to perform, with the implication that each role will be handled by a different server.
The Hub Transport role is the one responsible for sending and receiving external emails.
In the real world of small to medium sized companies, a single Exchange server is likely to be performing all the various roles.

Open Exchange Management Console
Click on the + next to Organization Configuration
Select Hub Transport and
select the Send Connectors tab:-

(If you can't see all the columns shown above, click View - Add/Remove Columns...)


Right-click on the existing Send Connector, select Properties and go to the Network tab.
Select "Route mail through the following smart hosts:" and click Add:-

Specify the first smarthost as shown below:-

Add all 3 of Arrowmail's smarthosts:-

Click Change... to set the authentication options.


Type the username and password we've issued to you below:-

Basic Authentication over TLS means emails are encrypted between your server and ours, which is a good idea except that Exchange 2007/2010 is fussy about the digital certificates used for encryption.
If you find your Send Connector won't route emails to our smarthosts then try clearing the Basic Authentication over TLS checkbox.


There shouldn't be anything that needs changing on the other 3 tabs, but we've shown below, what they should typically look like.

The General tab:-

The Address Space tab:-

The Source Server tab:-

When you've finished, the Send Connector should look like this:-

The changes you've made to the Send Connector will take effect straight away without you having to reboot the server or restart any services.

What if you don't use Exchange as your in-house Mail-server?

Many mail-server programs, other than Exchange, can take advantage of multiple smarthosts. However, if the one you're using use can only be configured for one smarthost, you should set it to use:-

smarthost.arrowmail.co.uk

We will make sure that this DNS name is always pointing to a functional mail-server.

If your mail-server isn't able to authenticate to our smarthosts then, as long as you are using a fixed public IP address, we can allow anonymous access from that specific IP address.

Stop your Exchange Server generating emails in response to incoming Spam

Now that you're paying for outgoing emails at something under 0.3p each, it's a good idea to make sure your are not sending out ones you don't need to.

By default, Exchange will accept emails to non-existent users and then generate an outgoing email to each sender, telling them, politely, that their email couldn't be delivered as the user doesn't exist.

Today, spammers often bombard an exchange server with large numbers of emails to addresses that have been guessed - usually wrongly.
Not only is it a waste of your monthly email allowance to reply to these emails but, the sender's address in the original email is likely to have been forged and so your server's reply will go to someone innocent of sending spam, who will now see you as spamming them.

It's very simple to enable "Recipient Filtering" so emails to non-existent users are rejected but, for some reason, this configuration step is often missed out by people setting up Exchange.

We had one customer where this type of email made up 80% of their total out-going emails, and we don't like them coming through our servers, even though we charge for them, as they mostly can't be delivered and, if they can, it risks annoying the recipient.

If you are about to configure your Exchange server to use our Smarthosts then, do everyone a favour by checking your Recipient Filtering settings.
Step-by-step instructions for configuring Recipient Filtering on Exchange 2003 and 2007 are here.

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How to Create a Sender Policy Framework Record to Authorise our Servers to send out your Company's Email

It's by no means essential, but if you use our smarthosts, it can help make email delivery more reliable if you create a special DNS record with whoever is handling the DNS for your domain name, which is usually your domain registrar.

This DNS record is to comply with the Sender Policy Framework (SPF) anti-spam initiative and it identifies our servers as being approved for sending emails from your domain.

It's a TXT record, which not all DNS servers or ISP control panels can handle, but if they can this is the record you need to add:-

mycompany.co.uk.   IN   TXT   "v=spf1 include:arrowmail.co.uk -all"

This is how it should appear in your DNS Zone File, including the inverted commas, but with your domain name substituted for mycompany.co.uk.

If you give us the logon details for your domain registrar's control panel we'll set it up for you.
If your current DNS servers can't handle TXT records you could move to DNS servers that can. This doesn't require you to change your domain registrar.
www.nettica.com will host your domain's DNS service, along with TXT records, on their servers forever for a one-off payment of US$40.

You can check that your SPF record has been successfully setup by sending an email to:-
check-auth@verifier.port25.com
Make sure that the From address you use is covered by the SPF record, no need to put anything in the Subject Line or the body of the email.
You should receive a reply containing something like the extract below, which also checks out any other anti-spam initiatives such as DomainKeys, DKIM, and Sender-ID:-

The SPF system has not yet been adopted widely enough to be a reliable method for identifying spam but, when sending emails, it can tip the balance your favour, especially with heavy-handed anti-spam systems.

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