Fax security guide

A page's journey, leg by leg, and the spots to watch.

On FaxTelecom, a fax covers two legs. The first, between your browser and our servers, is encrypted over HTTPS; there the file is used only for sending and then deleted automatically. The second, from our servers to the recipient's fax machine, runs over the telephone network, now largely carried as voice over IP, with no encryption: that is a limit of the fax protocol, identical for every provider. In practice, incidents seldom come from a tapped line. They start with a wrong digit, a machine anyone can walk up to, or a memory that was never wiped.

Weak spots, from most common to rarest

This ranking follows the incidents that actually happen. Technical interception comes last.

  1. A misdialled number

    Swap two digits and the fax lands with a stranger. As far as the system is concerned, it worked: a machine answered and accepted the pages. There is no way to pull the document back afterwards.

  2. A fax machine in an open area

    On arrival, the page prints into an output tray anyone can browse: reception desk, open-plan office, copy room. The longer it sits there, the more potential readers it gets.

  3. Copies that pile up

    A multifunction printer often keeps processed documents in its memory or on a hard drive, and some setups forward incoming faxes to a shared mailbox automatically. Every extra copy is one more place to secure.

  4. An unencrypted line

    On the last leg, fax signals travel in the clear, either analogue or wrapped in T.38 over IP networks. Intercepting them requires access to a carrier's infrastructure: possible, but far rarer than the three cases above.

What FaxTelecom takes care of

And, just as plainly, what no online fax service can promise.

Encrypted upload
The PDF you upload travels over HTTPS to our servers. Between your device and our infrastructure, nobody can read it. The next link in the chain, the phone line, cannot be encrypted by anyone.
Automatic deletion
The file serves only to build and transmit the fax. Once sending is over, it is erased without you lifting a finger; we put it to no other use.
A confirmation step before anything leaves
Nothing goes out until you click the link we email you, then let a countdown of about 55 seconds run, which you can stop at any point. One last chance to double-check the number.
Your document, untouched
The only addition is the cover page built from your form fields. No banners, no ads, no sales message on your pages.

Five careful habits

  1. Take the number from the source

    Copy it from an official document of the other party rather than an old address book, pick the right country in the form and compare digit by digit before confirming. Our country-code directory helps clear up any doubt.

  2. Give a heads-up

    A quick call or text along the lines of "I'm faxing the file in five minutes", and the recipient stands by the machine. The page doesn't linger in the tray.

  3. Take care over the cover page

    FaxTelecom builds it from your fields: name a specific recipient, write a clear subject and add a line in the message asking to be told of any misdelivery. It steers whoever finds the sheet.

  4. Send only what is needed

    Before you create the PDF, drop the appendix pages and black out anything superfluous: a full IBAN, a tax ID, medical history unrelated to the request. A slimmer document exposes less if something goes wrong.

  5. Keep proof of sending

    The PDF receipts option (€2.99 incl. VAT, charged only on actual delivery) records the request and then the transmission. If you doubt where the fax went, you have dated evidence to act on quickly.

Limits worth knowing

End-to-end encrypted fax does not exist in everyday use. ITU-T Recommendation T.30 does describe optional security mechanisms, but fax machines in service almost never implement them. Any service promising encryption all the way to the recipient's paper would be claiming more than the technology allows.

Nor does a fax say anything about what happens after printing: who picks up the sheet, who copies it, where it gets filed. It shows that a machine connected to a number accepted some pages, not that a given person read them. For highly sensitive information, if the other party offers a secure messaging service or an encrypted exchange platform, use that instead.

Your questions

Can my fax be intercepted?
Between your browser and FaxTelecom, the connection is encrypted with HTTPS. On the phone line to the recipient, the signal is not encrypted; intercepting it, however, takes access to a carrier's equipment. The more concrete risk remains a wrong number or a page left on the machine.
How long does FaxTelecom keep my PDF?
Only for as long as sending takes. Once the transmission ends, the file is removed automatically. We keep no copy that anyone could look up.
What should I do if I faxed the wrong number?
If you can reach whoever holds the number, ask them to destroy the document. Write down the time and what was sent, then alert the person in charge of data protection in your organisation. If the document held personal data, record-keeping and possibly notification duties may apply: our GDPR page sets them out.
Is fax suitable for health documents?
It is still widely used between doctors, pharmacies and hospitals, often at their request. That calls for extra care: number checked, recipient warned, content cut down to what is necessary. The rules of your profession or institution take precedence; check with the person responsible.

Where to go next

Hand-picked pages to help you prepare, send or prove your fax.

On the same topic