Unsolicited marketing and, even worse, fraudulent calls are unfortunately very common nowadays. Although total protection is impossible, the CERN Telephony Service has implemented several mechanisms to reduce such annoying calls to all CERN telephone numbers, whether landline or mobile. Remember that the mantra “Stop – Think – Don’t click” also applies to phone calls – just replace “click” by “talk”, stop your conversation and hang up if you have any doubts. Also remember that messaging applications (e.g. WhatsApp) and text messages are widely abused for illicit purposes. Malicious links or URLs are just one click away. The amount of vishing attempts and shock calls is increasing. If you doubt the authenticity of a displayed telephone number or messaging contact: Never disclose personal or confidential information: companies, hospitals, police officers, etc., will never ask you for any of your passwords, credit card numbers or other personal information over the phone or messaging app; Hang up if they request personal information, seem suspicious or threaten you; If you unwittingly provided your bank details or made a payment, contact your bank immediately; Report the attempted fraud: To Computer Security if CERN is involved; Fill out an NCSC Report if it is on your personal Swiss number; Follow these French recommendations if it is on your personal French number: Démarchage téléphonique abusif, spam vocal ou par SMS (abusive telephone solicitation, voice or text message spam) Escroquerie (scam) Call filtering at CERN To better protect you, CERN has implemented three layers of call filtering that are applied by our Telco operator, by the CERN Telephony Service and at the user level. Please note, however, that these spam filters can only offer a certain degree of protection, as new numbers need to be added constantly and telephone numbers can be faked by the caller (spoofing). Swisscom call filtering Incoming calls to CERN mobile and landline numbers are filtered by Swisscom according to an updated list of known spammers. Swisscom’s call filtering works like an email anti-spam system: background software checks the incoming call before it is established and decides if it is legitimate or not. If the call is blocked, the person being called won’t receive any notification. CERN fixed telephony call filtering In addition, the CERN Telephony Service, in collaboration with the CERN Computer Security Office, blocks certain numbers that have been reported by users to be fraudulent or annoying. Again, if the call is blocked, you won’t be notified. Personal call filtering Finally, you can manage your own list of numbers or prefixes to be blocked in addition to the Swisscom and CERN filters. For the CERNphone application (mobile or desktop): Via the CERNphone User Portal, select the CERNphone number to which you would like to apply the spam filter, go to “Settings” and add any number or prefix to be blocked via the “Spam filters” tab: For your CERN mobile phone: Via Swisscom’s cockpit, select “Call settings” under the “Settings” tab: And add any number or prefix under “Manually blocked numbers”: Android and iPhone call filtering Both Android and iPhone offer personal call filtering for their terminals. Please be aware that the configuration is terminal-dependent, so you will need replicate it if you change your phone: Android instructions iPhone instructions Support Should you have any questions, don’t hesitate to contact telecom services support.