E-mail spam, also called junk email or unsolicited bulk email (UBE), is now an unfortunate fact of life for most internet users. GreenNet does more than most to remove spam. What can you do to reduce your chance of getting spam, or to deal with it if you do?

Avoiding spam

Avoid posting your private address on a website

The most common means by which spammers can obtain your email address, and sometimes glean other details about you, is from web pages with the address displayed for all to see. The second most common way is from when you sign up to some site or “service” that then sells your address to spammers.

In both these cases you can use a disposable alias address, which we can set up for you – just let us know what address or addresses you would like. Alternatively, create your own disposable address using a ‘+’ sign: for instance, if you have the address example@gn.apc.org, you can already receive email at example+extension-marker@gn.apc.org (if you have your email forwarded elsewhere, we also forward this extension). Having multiple addresses going to the same mailbox means that you can let only your trusted contacts have one address, but use the other address to collect bulk email. You can deal with incoming email differently according to the address it is sent to, or in the worst case we can invalidate that address if it starts receiving too much spam. The disposable alias is particularly useful if you are posting something to a forum which shows email addresses.

If you have a web page, then a ‘mailto’ link is very convenient for anybody browsing, because they can click on that link and use their usual e-mail software to compose and send you a message. However, it is also convenient for spammers. Therefore people often either set up a mail form (see here) or remove the mailto link and show their email address as an image or display it using Javascript. For more information on possible ways of avoiding an address being harvested, please see our article on obfuscating email addresses on a website.

For privacy reasons, if you are sending an email to a large number of people, consider putting the addresses in the Bcc (blind carbon-copy) so that the full list is not visible to the recipients.

Never buy anything from spammers

Very few people actually ever do buy anything advertised in spam, but because the cost to the sender is often negligible, millions of spam emails can be sent to attract one punter. If everyone boycotted products that were ‘spamvertised’, it would greatly reduce the amount of unsolicited commercial email. Merely clicking on a link or showing interest may also encourage spammers. And of course there may be an ulterior motive to spam: something that appears to be trying to sell pornographic websites, for example, may be an attempt to defraud you in other ways or to infect your computer with a Trojan horse.

Just delete spam. If you ever reply to it, be aware that this may confirm to the spammers that your email address is valid. (You may also want to change the ‘real name’ of the identity you send from to prevent that also being added to their database. Using variations of a name may also have an effect like using an alias, so that you can tell where the spammers ultimately obtained your address from.)

For similar reasons, do not click on links in spam and either turn off the preview facility in your email program (for example, in Outlook Express/Windows Mail, go to View > Layout then untick Preview pane) and/or make sure that it is set not to download images. To stop images being downloaded automatically:

  • in Outlook Express, go to Tools > Options > Security and tick ‘block images and external content’
  • in Eudora, Tools > Options > Display > untick ‘automatically download HTML graphics’.
  • Thunderbird and KMail do this automatically

If you have email forwarded from a non-GreenNet address

If you have email forwarded from an address that is not hosted at GreenNet, you may well find that you get a significant amount of spam, the vast majority of which is sent via the non-GreenNet address. That is mostly because we cannot apply greylisting after it has been accepted by whoever services your domain. We will still quarantine a lot of spam that is forwarded, but this is less effective without greylisting, and our suggested solution is usually to have to the domain (or at least the mail handling) transferred to GreenNet. Contact us for advice on how to do this.

If you have a domain name

If you have your own domain name, say example.org, you may be used to having a catch-all address so that you receive email to anything@example.org. In fact, this allows you to have any number of alias addresses. The problem is that in some cases this can also attract a lot of spam and ‘backscatter’. Backscatter is a result of your domain name being forged, with spam coming from SomeCompletelyMadeupAddress@example.org, which results in all the bounces and out-of-office replies coming back to you as the owner of example.org. You might want to reconsider the catch-all, and in the meantime use a pattern for all your aliases (such as firstname.lastname@ or lists-xxx@), so that we could later block all email that does not match the pattern.

An alternative countermeasure is to ask us to set up an SPF record on the domain. This is simply a way of announcing to mail servers around the world that if an email claims to come from your domain but wasn’t sent through GreenNet (or some other set of outgoing servers you might use), then it is either likely to be spam (‘SPF softfail’) or is definitely spam (‘SPF fail’). One of the advantages of doing this is that it dissuades spammers from spoofing your domain, as they know their junk emails are much more likely to get bounced or discarded; also if your domain is spoofed, then SPF means some systems are likely to recognise it as spam, and less likely to send you the backscatter. We would set up an SPF record automatically on all domains, but unless you tell us, we aren’t sure if, for example, you might also have someone in your organisation whose email program is set up to use the SMTP server of another broadband supplier to relay outgoing email.

Dealing with spam

If your email address is already well-known to spammers, you have a few options to reduce the amount of spam that address receives:

  • Train the anti-spam features on your personal email client. Thunderbird and Apple Mail are two email programs (email clients) that allow you to mark spam you receive until they have ‘learned’ what is likely to be spam. Once you’ve trained it with several dozen messages, you can set the client to move all suspected junk to the junk folder.
  • Similarly, set a filter to move email that GreenNet has detected as spam to the junk folder on your local computer. For more information, see our page on spam filtering or click on the spam filter tag to find instructions for your particular email program.
  • Train the GreenNet filter to recognise the messages as spam. You can do this by forwarding the message as an attachment to an address we can give you (see below). This will also report the message to other global spam databases and so helps everybody.
  • Ask us to block the sender, or otherwise report spam.

If you are getting email that you don’t exactly recognise, but think you might have subscribed to a similar list, it’s a matter of personal judgement whether you treat it as normal, legitimate email and so ask to be removed from their address book by for example clicking on an unsubscribe link or writing to the sender; or whether you are sufficiently sure that it is unsolicited and report it as spam. Remember that not all unwanted email is spam – for it to be spam, either you have never explicitly consented to receive it, or you have explicitly withdrawn that consent.

Reporting spam

If you receive junk email, who should you complain to? Well, the sender seems the obvious place, but with spam of course the sender’s email address is most commonly a forgery, rather impolitely denying you the opportunity to respond to the right person. Even were it not forged, you don’t want to give the sender any more personal details than they already have. However, if there is a telephone number in the spam, and it’s not international or premium-rate, you could complain that way – enough time spent dealing with complaints, and spamming should cease to be viable.

So in most cases you will want to tell the sender’s service provider that their service is being abused. The question is, how do you know who to write to? Well, each email includes ‘headers’, some of which are normally invisible and include information about the email source – how you see the headers or ‘source’ varies between different email software. In the message’s full headers are ‘Received’ lines tracing how the message got to you. The ones at the top are those most recently added as they message passes through GreenNet, while the ones below will show the IP addresses of servers the message passed through earlier. For example

Received: from mail.ideam.gov.co (mail.ideam.gov.co []) by mail.gn.apc.org (Postfix) with ESMTP id A576DF435C for ; Wed, 13 Aug 2008 22:08:40 +0100 (BST)
Received: from bondinvestor.com (unknown []) by mail.ideam.gov.co (Postfix) with ESMTP id 53A26474A for ; Wed, 13 Aug 2008 15:52:12 -0500 (COT)

The top half was added by GreenNet, and shows the spam was sent to us though a Colombian government server. The second line ‘bondinvestor.com’ is not verified (‘unknown’), and could be a forgery. We would need to find the reporting address for the network In any case, mail.ideam.gov.co should not be relaying spam (which seems to be in Russian rather than Spanish), so you can complain to abuse@ the domain name, ideam.gov.co. Similarly, if any spam is ever sent from GreenNet (whether from a compromised website or a compromised email account), the abuse address people would report it to would be abuse@gn.apc.org.

That’s the principle of reporting email, but it all seems very complicated and hard work for a bit of junk email. Fortunately there are ways to simplify the process, the most popular of which is SpamCop.Net. You can register with SpamCop, and either send email as an attachment to a personalised address, or log in to their site and paste it in. SpamCop forwards the report to the responsible system administrator, and may also decide to add the sender network to a blocklist, preventing other people from getting similar spam. For reporting phishing and other fraud to Consumer Direct and so on, see here.

If the service provider is apparently slow to enforce their own terms of service, and the problem is severe, people can complain to the service provider’s ‘upstream’ provider, that is whoever provides an internet connection to them.

If you report spam to GreenNet, we can take action on your behalf, with other system administrators if needed.

How to report

To report spam to an ISP, or to SpamCop, or to GreenNet (either the automatic spam address we can give you, or to support@gn.apc.org), you need to include the full headers, which include normally invisible information about the email’s origin. The best way of doing this usually is to forward the email as an attachment. See How to forward an email as an attachment.

Avoiding sending spam

See elsewhere on this site for more information on.

  • Ensure software on your desktop and on any website is up-to-date.
  • Windows users should have anti-virus and anti-spyware software to check for “key loggers” that might steal passwords.
  • Never give your password(s) out by email. Also try to avoid using social networking sites claiming to “easily invite your friends/contacts”.
  • Don’t pass on chain letters or virus warnings.
  • Be careful with “Reply To All”, and there’s very rarely any reason to send to everyone in your address book. Thunderbird allows you to keep “Collected addresses” of one-off correspondents separate from a core address book.

These apply in particular to people with mailing lists:

  • Never buy lists of email addresses from anyone.
  • Ensure that any online subscription mechanism is defended against automated submissions, either by you approving subscriptions, email confirmation, or a captcha.
  • Have your own privacy policy in place, and when importing a list check that everyone has consented to receive the type of information you are proposing. When any new list is set up, you may want to put unsubscribe information prominently in the first paragraph of the first message.
  • If you have an additional supporter database, ensure that requests to unsubscribe do remove email addresses both from the database and the list. You may therefore find the Mailman option to “get notices of subscribes and unsubscribes” is best left on. Do not do a mass subscribe of an outdated copy of the contacts database.

So why is it called “spam” anyway?

Waitress: We’ve got egg and spam; egg bacon and spam; egg bacon sausage and spam; spam bacon sausage and spam; spam egg spam spam bacon and spam; spam sausage spam spam bacon spam tomato and spam;
Vikings: Spam spam spam spam…
Waitress: …spam spam spam egg and spam; spam spam spam spam spam spam baked beans spam spam spam or Lobster Thermidor a Crevette with a mornay sauce served in a Provencale manner with shallots and aubergines garnished with truffle pate, brandy and with a fried egg on top and spam.
Woman customer: Have you got anything without spam?

Monty Python

Further information

For more information see GreenNet’s guide to spam

Also if you’re a busy campaigner, Veggies Catering Campaign have a nice article on how to efficiently sort through a mixture of spam, bacon, tofu and the genuine nut roast.