Receiving silent or 'ghost' calls on your SIP phone

Receiving silent or 'ghost' calls on your SIP phone

Some of our users complain that they receive unwanted or ghost calls on their VOIP phone lines where they pick up the phone and nobody is there and this might happen several times a day or week.

The first thing you should do is check the Tech Connections Internet portal to see if the calls came from Tech Connections Internet and from the PSTN (telephone network), by logging into our customer portal and visiting the Account/Records page:


If you see the calls listed at the times you received them, then you are receiving Spam calls from the PSTN and so there are a few options.  If you do not see the calls listed skip to the next section below.

1. You can blacklist the Calling phone numbers by going to the Voice tab, clicking on your phone number and then selecting "Caller ID, Privacy and Intercom" from the Incoming calls drop down menu.  In these settings you will find a Blacklisted Callers section where you can enter a list of phone numbers you wish to blacklist from calling you.

2. If the Caller number is anonymous/blocked then you can reject anonymous callers to your number in the same section as indicated above.  There is a checkbox labelled "Reject all anonymous calls?" which you can tick.

3. You can screen incoming calls so that callers have to announce themselves and you can choose whether to accept or reject the call.  Click here to view how call screening works.

Silent or ghost calls that do not appear in our call records.

What you are likely experiencing is SPAM calls hitting your VOIP device directly from the Internet.  This typically means that your SIP port 5060 or 5061 is open to the internet at large which means that anybody on the Internet can send SIP traffic directly to your VOIP device which is not recommended.  This may be because your VOIP service is hosted on your router/WAN port or you have setup 'port forwarding' to forward SIP calls to your SIP device on your Local network.

These days there are a LOT of SIP scanners on the Internet trying to REGISTER and INVITE (call) any devices listening on ports 5060 and 5061 (SIP signalling ports).  When one of these scans happens you will experience a 'ghost' call.

We recommend you take you SIP device off the public internet as it should not be necessary to have your device accessible from the public internet to work with our service.  Remove any port forwarding rules for ports 5060 and 5061 pointing at your VOIP device.  If for some reason this is not possible then you should apply firewall rules or an access control list to limit the access to these ports to just the Tech Connections Internet network.  Please see this article for which IP addresses to permit traffic from.  Generally speaking though you should not ever need to do port forwarding to make VOIP work with our service.  We can handle SIP devices behind NAT and most firewalls.

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