A lot of companies and mail services put little invisible images into their mails that contain a personalized url. Whenever you open their mail, this image is loaded from the server and the company knows that you opened their mail.
<img src="http://tracker.com/trk?yourid=<some_random_string>"
width="1"
height="1"
style="display:none !important;"
alt="">
This is how they know that their spam has reached you -- a good start to send more.
There are tools that show you, where programs want to connect, for example Little Snitch. This is great to discover a new url that is not on the list yet.
The easiest and free way to block tracking is however adding the urls to your hosts
file. This makes your system re-route the tracking-links into nirvana.
If you find new urls, create a pull request or an issue to add them to the list.
0.0.0.0 track.mixmax.com
0.0.0.0 securepubads.g.doubleclick.net
0.0.0.0 click.mailer.atlassian.com
0.0.0.0 marketing.intercom-mail-200.com
0.0.0.0 mailchimp.com
0.0.0.0 list-manage.com
0.0.0.0 cl.exct.net
0.0.0.0 emailtracking.azure.com
0.0.0.0 trker1.azalead.com
0.0.0.0 mkto-k0023.com
0.0.0.0 maileon.com
0.0.0.0 xqueue.de
0.0.0.0 t.yesware.com
0.0.0.0 track.getsidekick.com
0.0.0.0 t.sigopn01.com
0.0.0.0 t.senaluno.com
0.0.0.0 t.senaldos.com
0.0.0.0 t.senaltres.com
0.0.0.0 t.senalquatro.com
0.0.0.0 t.senalcinco.com
0.0.0.0 t.sigopn02.com
0.0.0.0 t.sigopn03.com
0.0.0.0 t.sigopn04.com
0.0.0.0 t.sigopn05.com
0.0.0.0 t.signauxun.com
0.0.0.0 t.signauxdeux.com
0.0.0.0 t.signauxtrois.com
0.0.0.0 t.signauxquatre.com
0.0.0.0 t.signauxcinq.com
0.0.0.0 t.signauxsix.com
0.0.0.0 t.signauxsept.com
0.0.0.0 t.signauxhuit.com
0.0.0.0 t.signauxdix.com
0.0.0.0 t.signauxneuf.com
0.0.0.0 t.signaleuna.com
0.0.0.0 t.signaledue.com
0.0.0.0 t.signaletre.com
0.0.0.0 t.signalequattro.com
0.0.0.0 t.signalecinque.com
0.0.0.0 t.strk01.email
0.0.0.0 t.strk02.email
0.0.0.0 t.strk03.email
0.0.0.0 t.strk04.email
0.0.0.0 t.strk05.email
0.0.0.0 t.strk06.email
0.0.0.0 t.strk07.email
0.0.0.0 t.strk08.email
0.0.0.0 t.strk09.email
0.0.0.0 t.strk10.email
0.0.0.0 t.strk11.email
0.0.0.0 t.strk12.email
0.0.0.0 t.strk13.email
0.0.0.0 t.sidekickopen01.com
0.0.0.0 t.sidekickopen02.com
0.0.0.0 t.sidekickopen03.com
0.0.0.0 t.sidekickopen04.com
0.0.0.0 t.sidekickopen05.com
0.0.0.0 t.sidekickopen06.com
0.0.0.0 t.sidekickopen07.com
0.0.0.0 t.sidekickopen08.com
0.0.0.0 t.sidekickopen09.com
0.0.0.0 t.sidekickopen10.com
0.0.0.0 t.sidekickopen11.com
0.0.0.0 t.sidekickopen12.com
0.0.0.0 mailtrack.io
0.0.0.0 mailstat.us
0.0.0.0 go.toutapp.com
0.0.0.0 app.outreach.io
0.0.0.0 tracking.cirrusinsight.com
0.0.0.0 app.yesware.com
0.0.0.0 t.yesware.com
0.0.0.0 mailfoogae.appspot.com
0.0.0.0 launchbit.com
0.0.0.0 cmail1.com
0.0.0.0 infusionsoft.com
0.0.0.0 via.intercom.io
0.0.0.0 mandrillapp.com
0.0.0.0 t.hsms06.com
0.0.0.0 app.relateiq.com
0.0.0.0 go.rjmetrics.com
0.0.0.0 web.frontapp.com
0.0.0.0 sendgrid.net
0.0.0.0 icptrack.com
0.0.0.0 click.icptrack.com
0.0.0.0 bl-1.com
0.0.0.0 links.mixmax.com
0.0.0.0 app.mixmax.com
0.0.0.0 ping.answerbook.com
0.0.0.0 constantcontact.com
0.0.0.0 google-analytics.com
0.0.0.0 mkt4477.com
0.0.0.0 api.mixpanel.com
0.0.0.0 mixpanel.com
0.0.0.0 list-manage.com
0.0.0.0 list-manage1.com
0.0.0.0 ihrgeld2016.com
0.0.0.0 doubleclick.net
0.0.0.0 webtrekk.net
0.0.0.0 elaine-asp.de
0.0.0.0 pstmrk.it
There are a lot of e-mail tracking tools online, for example:
- Yesware http://www.yesware.com
- MailChimp http://www.mailchimp.com
- Sidekick by Hubspot https://app.getsidekick.com
- ToutApp https://www1.toutapp.com
- Streak https://www.streak.com
- ContactMonkey http://www.contactmonkey.com
- MailTrack https://mailtrack.io
- SalesHandy https://www.saleshandy.com
- Maileon http://maileon.com & https://www.xqueue.de
If you get an e-mail by someone who might have an interest in wheter you read it (i.e. marketing-people, companies, shops), look at the source (*) and try to find something like the above code. It is usually at the very end of the mail. Create an issue with the url and I'll add it to the list!
- macOS Mail:
View
>Message
>Raw Source
- Outlook: Right-click anywhere in the message and select
View Source
- Thunderbird: Select
View
>Message Source
(or hitCtrl+U
) - GMail: Open message > Click on the down arrow next to the reply arrow >
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