Email Filtering image - No Junk Mail sign on letterbox

Email Filtering

Stop all the email-borne threats, and there are lots of them, ever making it to your company’s email system.

Don’t put up with all those annoying time-wasters filling up your Inbox.

We offer an off-site cloud-based email filtering system to stop the bad stuff ever reaching your company’s mail-server.

If hackers can’t find your mail-server they won’t be wasting your bandwidth trying to guess passwords or looking for weaknesses in your security.

What Exactly Do We Mean By Spam?

“Spam” is a convenient term to cover all the emails you don’t want to receive (That doesn’t include the reminders from HMRC to fill out your tax return.)
Unwanted emails fall into these categories:-

Type of SpamWhat Is The Purpose of the Spam?Who Is Sending It?How much of a threat are they?
Emails with an attachment that contains a virus or a link to download a virus.To find logon or other other personal details in order to steal your money.
To enlist your computer into a botnet, without you realising it, in order to send spam or mine Bitcoins.
Very clever people who are experts in programming, perhaps working for criminal gangs, in places like Russia where the rule of law does not apply.Massive.
If your company is infected by Ransomware you will lose £1000s.
Fake emails pretending to be from a well-known company, a work colleague or a friend.To steal money from youRanges from very clever criminals to have-a-go amateurs.The best ones are hard to spot and can cost you £1000s if you fall for them.
Marketing emails from legitimate companies you haven’t agreed to receive.To sell you their goodsOver-zealous people in the company that are ignoring or don’t know the rules on sending unsolicited emails.No threat. Just annoying. You might be able to unsubscribe.
Marketing emails from dodgy people you wouldn’t want to have any dealings with.Usually to sell you their goodsUnscrupulous marketers using all sorts of tricks to get their message to you.No threat. Just annoying

There are other types unwanted emails that we don’t consider to be spam:-

  • Marketing emails from genuine companies that you have agreed to receive – maybe you subscribed by accident, you’ve forgotten or someone else subscribed for you.
    You just need to find the Unsubscribe instructions which are usually at the bottom of the email.
  • Genuine emails sent in error or to the wrong person – we all make mistakes.

Why Does Spam Still Exist?

I will rid the Internet of spam within 2 years!

Bill Gates, speaking at the World Economic Forum in 2004
  • The cost of sending 1000s of spam emails ranges from very cheap to free. If one person in 10,000 buys their product/falls for their trick it’s a win.
  • The Internet reaches parts of the world that the rule-of-law does not.
  • Money paid in Bitcoins is untraceable and unrecoverable.
  • It’s still too easy to get access to a genuine UK bank account and then use it as staging post to get money, stolen via bank transfers, out of the country.
  • There are some really clever people working for the dark side.
  • People are gullible – it just takes one person in a company to download a Ransomware virus.
  • Information that is readily available on the Internet means that people in remote parts of the world can target you specifically and there are more people that you might imagine willing to engage in criminal activity. Perhaps to people in 3rd world countries, people in rich western countries are “fair game”.
  • There is nobody in charge of enforcing email standards. The initiatives developed to fight spam have not been adopted widely enough for them to be used to determine, for certain, if an email really is spam, or if it’s from a genuine company that hasn’t implemented them. These measures can only therefore be used as a guide.
  • Anyone can get a free untraceable email account from Gmail, Yahoo, Hotmail etc. to use for sending spam for maybe a day before they are found out and the account suspended. Another day another account. Maybe the have a cheap source of domains names so register a new domain for every spam run.
  • There seems an unlimited supply of websites/mailboxes with easily guessed passwords enabling spammers to send out emails from genuine addresses.

Can Arrowmail’s Email Filtering Service Block All Of Your unwanted emails without losing any of your Wanted Emails?

We can do an excellent job but, full disclosure, for most of the reasons listed in the previous paragraph, we can’t guarantee to get it right 100% of the time – nobody can.
Of all the things we do at Arrowmail, we put the most effort into keeping up with the latest spammer tricks and looking for ways to combat them.

To be thoroughly effective we need your help:-

  • Be suspicious. Assume that any request that involves doing something with money is a trick and make a phone call to check before doing anything you might regret. Assume any warning about a computer related problem that requires you to do something urgently is false – check with the IT department.
  • Be vigilant. In your Inbox, don’t just look at the name of the person who sent you the email, look at the email address as well. If the email is from a colleague then the email address will be at your company’s domain. If there’s a link in an email, hover your mouse over it to make sure it’s actually taking you to where it says.
  • You can forward any suspicious emails that get through to your Inbox on to us for analysis at

Since the emergence of Ransomware we’ve become stricter and not so accommodating to email systems that, although genuine, have not been set up professionally. Usually we can set exceptions where emails from one of your regular correspondents are triggering some of our filters, without compromising their effectiveness.

Any email that gets filtered out is kept for 6 months in case it was a false positive and needs to be restored.

What are your Filtering options?

  • The simplest and safest way is just to leave us to block the spam. If an email is an attempt to install ransomware on your network then it only takes one person to make a mistake once for it to succeed.
    If any of your regular correspondents are getting blocked then we’ll investigate why, restore the missing emails and stop it happening in future unless they are doing something really bad like their mail-server is on a blacklist in which case they’ll need to fix it as they will be having great difficulty sending emails to anyone.
  • We can just mark emails as spam and forward them on to your mail-server where people can use an Inbox Rule to automatically move these emails to their Junk Email folder.
  • Emails determined to be spam can all be forwarded to a specific mailbox on your server where the least gullible person in your organisation can check for any genuine emails.

How does our service work?

  • You change the DNS MX records for the company domains that you want filtering so that they point to our servers, which means your emails then come directly to our servers.
  • You tell us the IP address or hostname of your mail-server for us to forward the emails to after filtering. This can optionally be over a different port number, to hide your server, and with authentication.

These are the MX records you need to set up.
Note that the Priority is the same in each case to spread the load across our 3 incoming servers and any other existing MX records should be deleted.

Mail ServersPriority

An Added Benefit of using our service – Lost Email Protection

If your company mail-server ever goes off-line, your incoming emails are held in a queue on our servers and attempts are made to resend them every 15 minutes, indefinitely. The people sending these emails, therefore, won’t get failure of delay messages and if your server is going to be down for an extended period we can forward copies of the waiting emails to an external address or a mailbox on our system so that you can read them and respond if necessary.

Email Filtering – Get a One Month free trial

“Free” means “Free” so you don’t need to pay anything upfront or set up any payment method.

Our email filtering service is in the Cloud and isn’t a program that you can download to your computer. You therefore need to be able to divert your incoming emails so that they pass through our servers before arriving in people’s inboxes. To do this you need to:-

  • Change the DNS MX records for the company domains that you want filtering to point to our servers so that your emails then come directly to our servers.
  • Tell us the IP address or hostname of your mail-server for us to forward the emails to after filtering. This can optionally be over a different port number, to hide your server, and with authentication.

Any problems and we’re here to sort them out – you’re not going to become a paying customer if you can’t get the service to work the way you want it to.

Ask us for a trial by emailing us at, phoning us on 0800 099 6480 or filling in this webform

  • We’ll contact you after a month and give you plenty of opportunity to reply and organise payment before suspending your account.
    Any problems and you can just set the MX records back to how they were previously.