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tcpdump Capture Filter Builder

Build validated libpcap filters for protocol, source, destination, and destination ports. Work locally without uploading network information.

Runs entirely on your deviceNo uploads, accounts, cookies, or personal tracking.

Build capture filter

Local processing · no input storage

Network tools
Used only in the generated command; no capture is started.
Select the format or assumption to use.
Enter the value to evaluate.
Enter the value to evaluate.
TCP/UDP only. Commas and inclusive ranges such as 1000-2000 are accepted.

Generates capture filters for tcpdump/libpcap, not Wireshark display filters. Uses numeric addresses without DNS resolution.

Enter your data, then select build capture filter.

Technical reference: libpcap filter syntax

1. Add your data

Enter your network data or load the worked example.

2. Choose the result

Build capture filter and review the result and assumptions.

3. Save it locally

Copy the result or download it for your engineering workflow.

About this tool

Use tcpdump Capture Filter Builder without an upload

Build validated libpcap filters for protocol, source, destination, and destination ports. Work locally without uploading network information.

The operation runs in the current browser tab. Tool input is not included in aggregate analytics, and the standalone download makes no analytics requests.

Network toolsDeveloper tools