Let’s say you just missed a phone call, and the caller didn’t leave a message. You’re wondering whether you missed an important call, but when you try to call back, there’s a recorded message saying the phone number doesn’t exist. Even worse, your phone’s call log doesn’t contain any specific information about the caller.
Chances are, you’ve just been called over a VoIP line, and it’s hard to trace—but not impossible.
VoIP stands for Voice over Internet Protocol, and this method of calling over the internet is fast becoming the norm for business calling.
How to Tell if It’s a VoIP Call
You can’t always tell whether a number comes from a VoIP service, but if your phone displays an unfamiliar area code, multiple zeros, or a sequence of random digits, it’s likely a VoIP call. It’s not always this easy to tell, though. Certain VoIP providers can make calls appear as if they originate from your same area code, or they might look like a normal mobile number.
Now, here’s where it becomes a little trickier. VoIP calls are made through an internet IP address. But guess what? That address can be shared by multiple numbers, like a single postal code serving many houses.
Not only that, the caller might have a different number assigned to them the next time they call, making it even harder to track.
Some VoIP numbers might pull a disappearing act when you try to call them back. And if the caller is using a VPN (Virtual Private Network), the data trail can turn into a real maze.
Tracing Fixed vs. Non-Fixed VoIP Numbers
Here’s where the difference between fixed and non-fixed VoIP numbers comes into play. Fixed VoIP services are typically associated with a specific physical location and are easier to trace. Non-fixed VoIP numbers, on the other hand, aren’t tied to a specific address, making them more elusive.
If you’re dealing with a non-fixed VoIP number that isn’t attached to a physical address, or if the number is shared, encrypted, or otherwise hidden, you might have difficulty finding the VoIP call’s origin on your own.
If you ever suspect that the caller is up to something sinister—potentially threatening or illegal—don’t play detective yourself. Reach out to the authorities, as they have a lot more tools at their disposal for tracing calls.
Check Your Phone’s Call Log
The first step in tracing a VoIP number is obviously to check your phone’s call log. The call log records all incoming and outgoing calls to your number.
On an iPhone, you can find your call log by opening the Phone app and tapping Recents at the bottom of the screen. Each entry in the list typically shows the caller’s name or phone number, the date and time of the call, and the call duration.
To see more details about a specific call, tap the More Info button next to the call entry. (This is typically represented by a circle with a lowercase i in the center.) This will display information such as the call length and whether it was an incoming or outgoing call.
The process is very similar on an Android, and in either case, you will be able to see the registered number for each caller. If it’s a number that looks legitimate, or if you see the caller’s name, mark down that information so you can use it in the next step.
Look Up the Phone Number
The next thing you’ll want to try is a reverse phone number lookup. This shouldn’t take much time, and it may help you discover who called, especially if it’s from a registered business. Several websites offer this service, and some even have an app to make it more convenient.
Whitepages, Spokeo, and TrueCaller are a few platforms with extensive caller databases, including individuals and VoIP phone numbers. To find your caller, simply visit one of these websites and enter the VoIP number you want to trace into the search bar. The service will then provide you with information about that number, such as the owner’s name and address.
While the reverse phone lookup method can work, it’s not totally foolproof. First of all, some VoIP numbers may be unavailable in these databases, particularly if they’re relatively new or were created with strict privacy settings. It’s also possible that the caller’s details may have changed. Finally, these services may ask you to register or charge fees for detailed information.
Analyze the Domain
If your business uses a VoIP system, you might be able to trace another VoIP caller’s origin from the domain listed in your call logs.
To find a call’s domain, log in to your VoIP dashboard and access your call details or call history. VoIP providers such as Nextiva display information about incoming and outgoing calls, similar to your mobile phone’s call log. These databases include call times and durations, caller names and numbers, and domain information.
An example of an entry might appear similar to the one below:
- Caller: John Doe
- Caller’s Number: +1-123-456-7890
- Domain: voipprovider.com
- Date/Time: 2023-10-19 10:30 AM
- Call Duration: 10 minutes
In this example, the VoIP call log shows the associated domain name, voipprovider.com.
A domain address may also appear as a string of numbers, such as 203.0.113.12, which represents the origin of the VoIP call. In other cases, the domain information may be encrypted and appear as a random string of numbers and letters.
Once you’ve identified the domain, you can trace it back to an IP address. Domain-to-IP conversion tools are available online, and you can use these to find the IP address associated with the domain in question.
Here are a few of your options for finding out who owns a domain and where it’s located:
- Domain Lookup—Use GoDaddy’s WHOIS domain lookup to find information about who owns a domain
- Domain to IP Converter—RankWatch’s free tool will give you a domain’s IP address and its general location
- IP Address Lookup—If you already know the IP address, Nord VPN’s IP Address Lookup will help you find the hostname and more precise geolocation of that caller.
Contact Your VoIP Service Provider
Your VoIP provider’s customer support may have access to more extensive call logs that include IP address information. This is especially relevant if you’re dealing with harassment or security concerns. (Though again, if you think the caller is trying to do something illegal, escalate the issue to authorities.)
However, even your service provider might not be able to trace a call if the IP address is used by multiple numbers, if the caller is using a VPN, or if the number was never registered properly in the first place.
Diagnose the IP Using a Tool Like Wireshark
This next step is rather technical and best done by an IT department or system administrator.
This method involves using a network packet analyzer, such as Wireshark, to trace the origin of VoIP calls. Here’s how you can use Wireshark if you’re extremely tech-savvy:
- Capture VoIP Traffic—Start Wireshark and initiate a packet capture on the network interface through which the VoIP call is passing. You should filter the capture to focus on the relevant traffic, which is typically VoIP packets. Common VoIP protocols include SIP, H.323, and RTP.
- Identify SIP or H.323 Signaling—Look for SIP or H.323 packets, which contain signaling information about the VoIP call. You can see the source IP address of the call initiator in these packets. Note that in some cases, these addresses may be obscured or encrypted due to security measures or network configuration.
- Analyze RTP Streams: If you want to trace the actual voice data, Wireshark can also capture and analyze RTP (Real-time Transport Protocol) streams. This can reveal the source and destination IP addresses and ports used for the audio stream.
While Wireshark may be able to yield accurate results, remember that Network Address Translation (NAT) and encryption can complicate the process. NAT often hides internal IP addresses, while encryption makes it challenging to intercept and understand the VoIP content.
Also, VoIP calls can be spoofed, and the originating IP addresses may not always be trustworthy. Remember, one of the highlights of VoIP services is the added privacy and versatility that these systems provide, especially to businesses.
Summary: Tracing a VoIP Call
If you’re trying to trace a VoIP call, for most people, a simple check in your call log and a domain or IP address lookup might solve your problem.
But if the caller is using a non-fixed VoIP number that isn’t attached to a physical address, or if the number is shared, encrypted, or otherwise hidden, you might have difficulty finding the VoIP call’s origin on your own.
If all this sounds like jargon to you, but you still really need that VoIP address—especially if it raises a security or legal concern—you should reach out to the authorities, who are better equipped to handle more serious issues.