Simplifying BGP Filtering with bgpq3

Simplifying BGP Filtering with bgpq3

As networks grow larger and more complex, managing BGP (Border Gateway Protocol) filters becomes increasingly challenging. The bgpq3 utility offers a solution to this problem by automating the generation of BGP filters based on RADB (Routing Arbiter Database) data. In this article, we will explore the features, options, and formatting capabilities of bgpq3 and showcase examples of its usage.

What is bgpq3?

bgpq3 is a command-line tool that generates configuration for BGP filters such as prefix-lists, extended access-lists, policy-statement terms, and as-path lists. It leverages RADB data to determine which prefixes, autonomous systems, as-sets, and route-sets should be included in the generated filters.

Key Features and Options

bgpq3 offers a variety of features and options to customize the generation of BGP filters. Some notable options include:

• Generation Modes: bgpq3 supports both IPv4 and IPv6 prefix/access-list generation. By default, it generates IPv4 filters, but you can specify the -6 flag to generate IPv6 filters.
• Aggregation: bgpq3 can aggregate generated filters to minimize the number of entries while ensuring that the aggregated filters accurately represent the original set.
• Formatting Flexibility: With the -F option, you can define a user-defined format for the generation of filters. This allows you to generate output in a format that suits your specific needs, whether it’s for routers or other programs/systems.
• Database Sources: The -S flag enables you to specify the database sources to be used for filtering. You can limit the sources to trusted databases, such as RIR (Regional Internet Registry) maintained databases, to ensure the accuracy of the generated filters.

Usage Examples

Let’s explore some examples to showcase the power and flexibility of bgpq3:

1. Generating Juniper prefix-filter for AS20597:
   bgpq3 -Jl eltel AS20597
   This command generates a named Juniper prefix-filter for AS20597, based on RADB data. The resulting configuration allows only specific prefixes from AS20597.

2. Generating Cisco prefix-list with aggregation for AS20597:
   bgpq3 -Al eltel AS20597
   This command generates a Cisco prefix-list for AS20597, taking advantage of the aggregation feature (-A) to make the prefix-filter more compact.

3. Generating advanced Juniper policy-statement with extra match conditions for AS20597:
   bgpq3 -AJEl eltel/specifics -r 29 -R 32 -M "community blackhole" AS20597
   This command generates a policy-statement for Juniper routers, incorporating extra match conditions, prefix-length limits, and hierarchical names. The resulting configuration allows more-specific routes for eltel networks, but only if they are marked with the specified community.

Conclusion

bgpq3 simplifies the management of BGP filters by automating the generation of configurations based on RADB data. With its powerful features, such as aggregation, formatting flexibility, and database source control, bgpq3 empowers network administrators to create accurate and efficient filters for their routers and devices. By streamlining the filtering process, bgpq3 saves valuable time and reduces the risk of misconfigurations in BGP routing. Try out bgpq3 and experience the benefits of automated BGP filtering.

Have any questions or suggestions? Feel free to ask in the comments section below.

References:
1. Routing Arbiter
2. draft-michaelson-4byte-as-representation-05
3. Cisco documentation
4. JunOS prefix-lists limitation
5. IOS-XR prefix-set limitation

Author: Blake Bradford