Troubleshooting auto-export with diagnostic commands

This article discusses the diagnostic commands available for troubleshooting auto-export.

The auto-export statement is particularly useful for configuring overlapping VPNs—VPN configurations where more than one VRF routing instance lists the same community route target in its vrf-import policy. The auto-export statement finds out which routing tables to export routes from and import routes to by examining the existing policy configuration.

Configuring routing-options auto-export on a routing instance binds the rt-export protocol module to it. Traditional vrf-import and vrf-export policies check for specific matches on other VRFs on the router. These policies trigger local intra-router prefix redistribution based on the RT communities without the need for BGP. The resulting behavior is similar to what would be expected from a prefix received from a remote PE over BGP.

Diagnostic commands used for diagnosing auto-export

The show route export command displays a list of routing tables that are currently participating in the export mechanism, either as importer or exporter or routes.

The ‘Export’ field will display a value of ‘Y’ if the table is currently exporting routes to other tables.

The ‘Routes’ field will display the number of routes exported from this table into other tables. If a route is exported to N different tables it counts once only.

The detailed display shows the tables importing and exporting a particular route target. In this example routes with community ‘100:1’ are being exported from the table customer2.inet.0 to the table ‘customer1.inet.0’. The same happens for community ‘65000:117’ being exported from customer2.inet.0 to ‘customer1.inet.0’.

Exported routes will display an ‘Announcement bit’ entry corresponding to this feature.

Traceoptions For Auto-export

If required, open a case with JTAC to further troubleshoot the issue.

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