PCAP File Extension

What is PCAP file?

PCAP is a file format used by applications for monitoring network traffic. Sniffer (for example, Wireshark), as such tools are usually referred to, logs packet data and saves it into a PCAP file. PCAP files allow users to inspect network traffic for given capture session (in off-line mode, as opposed to real-time mode). Analyzing and auditing network traffic is an essential practice that facilitates network performance optimization and cyberattack prevention.

What is a sniffer?

Sniffer is a type of software tool that can capture and analyze network traffic. The tool ‘listens’ to network traffic on given network by switching a network interface it listens on into promiscuous mode, so that it can see all the traffic on given network, including data not addressed to this particular interface. Running a sniffer tool on a router on network-attached computer doesn’t require promiscuous to be used. Sniffer may also refer to an electronic device for monitoring network traffic.

Wireshark software application

Wireshark is a free sniffer tool available for Windows, Linux, and Mac systems. The tool offers many features and functions that made it the most popular network traffic analysis tool. Wireshark is used by both professional laboratories or IT companies and individual users for personal use. Ethereal was the original name for this tool until May 2006 when it was renamed Wireshark. Ethereal used the PCAP file format to store network traffic data.

Programs which support PCAP file extension

Below you will find an index of software programs that can be used to open PCAP files divided into 2 categories according to system platform supported. Files with PCAP suffix can be copied to any mobile device or system platform, but it may not be possible to open them properly on target system.

Updated: 11/28/2021

How to open file with PCAP extension?

There can be multiple causes why you have problems with opening PCAP files on given system. What is important, all common issues related to files with PCAP extension can be resolved by the users themselves. The process is quick and doesn’t involve an IT expert. The list below will guide you through the process of addressing the encountered problem.

Step 1. Get the Wireshark

Problems with opening and working with PCAP files are most probably having to do with no proper software compatible with PCAP files being present on your machine. This issue can be addressed by downloading and installing Wireshark or different compatible program, such as WinDump, NetworkMiner, tcpdump. On the top of the page a list that contains all programs grouped based on operating systems supported can be found. One of the most risk-free method of downloading software is using links provided by official distributors. Visit Wireshark website and download the installer.

Step 2. Update Wireshark to the latest version

If you already have Wireshark installed on your systems and PCAP files are still not opened properly, check if you have the latest version of the software. Software developers may implement support for more modern file formats in updated versions of their products. The reason that Wireshark cannot handle files with PCAP may be that the software is outdated. All of the file formats that were handled just fine by the previous versions of given program should be also possible to open using Wireshark.

Step 3. Associate Packet Capture Data files with Wireshark

If you have the latest version of Wireshark installed and the problem persists, select it as the default program to be used to manage PCAP on your device. The method is quite simple and varies little across operating systems.

Selecting the first-choice application in Windows

• Clicking the PCAP with right mouse button will bring a menu from which you should select the Open with option
• Next, select the Choose another app option and then using More apps open the list of available applications
• Finally select Look for another app on this PC, point to the folder where Wireshark is installed, check the Always use this app to open PCAP files box and conform your selection by clicking OK button

Selecting the first-choice application in Mac OS

• Right-click the PCAP file and select Information
• Find the Open with option – click the title if its hidden
• Select Wireshark and click Change for all...
• If you followed the previous steps a message should appear: This change will be applied to all files with PCAP extension. Next, click the Continue button to finalize the process.

Step 4. Check the PCAP for errors

You closely followed the steps listed in points 1-3, but the problem is still present? You should check whether the file is a proper PCAP file. It is probable that the file is corrupted and thus cannot be accessed.

1. Check the PCAP file for viruses or malware

If the file is infected, the malware that resides in the PCAP file hinders attempts to open it. It is advised to scan the system for viruses and malware as soon as possible or use an online antivirus scanner. If the scanner detected that the PCAP file is unsafe, proceed as instructed by the antivirus program to neutralize the threat.

2. Verify that the PCAP file’s structure is intact

If the PCAP file was sent to you by someone else, ask this person to resend the file to you. The file might have been copied erroneously and the data lost integrity, which precludes from accessing the file. When downloading the file with PCAP extension from the internet an error may occurred resulting in incomplete file. Try downloading the file again.

3. Check if the user that you are logged as has administrative privileges.

There is a possibility that the file in question can only be accessed by users with sufficient system privileges. Log out of your current account and log in to an account with sufficient access privileges. Then open the Packet Capture Data file.

4. Verify that your device fulfills the requirements to be able to open Wireshark

The operating systems may note enough free resources to run the application that support PCAP files. Close all running programs and try opening the PCAP file.

5. Check if you have the latest updates to the operating system and drivers

Up-to-date system and drivers not only makes your computer more secure, but also may solve problems with Packet Capture Data file. It is possible that one of the available system or driver updates may solve the problems with PCAP files affecting older versions of given software.

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