What community formats can I test?

You can test AS:value entries such as 65000:100 and well-known names such as no-export, no-advertise, internet, and local-AS.

How should I enter the community set?

Enter one community per line in the Community Set field.

How should I format an AS-path?

Enter AS numbers separated by spaces, with one sample path per line.

Which vendor outputs are available?

The tool generates output for Cisco IOS-XE route-maps, Juniper Junos policy-statements, and FRRouting route-maps.

Can regex matching be case-sensitive?

Yes. Enable Case-Sensitive Regex when matching case-sensitive text values.

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BGP Community Regex Tester and Looking-Glass Explainer

Validate RFC 8294 BGP community regex patterns against a set of communities, match sample AS-paths, and generate Cisco/Juniper/FRR route-policy output.

Details

What this tool helps you do

BGP communities (RFC 8294) are 32-bit tags attached to routes, formatted as AS:value (e.g. 65000:100) or as well-known names (no-export, no-advertise, internet, local-AS). Network engineers use regex on community attributes and AS-paths inside route-maps and policy-statements to filter, tag, and steer traffic. This tool tests your community regex against a set, shows which communities match, runs an AS-path regex, and emits ready-to-paste vendor configurations.

Execution

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Prepared example runs

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2 examples

Match BGP communities from a specific AS

Test a regex that matches all communities from AS65000 against a mixed set, then generate a Cisco route-map.

{
  "type": "text"
}

Generate a Juniper AS-path filter

Match sample AS-paths transiting AS65000 and emit a Junos policy-statement.

{
  "type": "text"
}

Inputs

Set the required fields, then run the tool.

6 options

ContentPaste or type the main input values.4

BGP Community RegextextOptionalCommunity Set (one per line)textareaOptionalAS-Path RegextextOptionalAS-Path (space-separated)textareaOptional

SettingsAdjust formats, ranges, numbers, and modes.1

Vendor OutputselectRequired

TogglesEnable or disable optional behavior.1

Case-Sensitive RegexcheckboxOptionalEnabled when checked

Result

Ready for a run

Run the tool to preview files, text, structured data, or streamed output here.

Samples

BGP Community Regex Tester and Looking-Glass Explainer

What this tool helps you do

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Prepared example runs

Inputs

Result

Examples that match this tool

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Inputs

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Key facts

Overview

When to use

How it works

Use cases

Examples

1. Test a provider community range

2. Find paths transiting an autonomous system

FAQ

Regex Replace Samples

Regex Pattern Alternatives

Regex Named Capture Groups

Common Regex Patterns

Regex to String Generator

Multi-Pattern Matcher

Named Group Tester

Regex Benchmark

Text Case, Encoding, and Normalization Conversion Tools

Text Tools

Text Analysis, Readability, and Content Inspection Tools

Text Redaction, Highlighting, and Presentation Formatting Tools

3. Check well-known BGP communities