V-283836

Discussion

These options are intended to be for the Hop-by-Hop header only. The optional and extensible natures of the IPv6 extension headers require higher scrutiny since many implementations do not always drop packets with headers that can be recognized. This could cause a denial of service on the target device. In addition, the type, length, value (TLV) formatting provides the ability for headers to be very large.

Check Content

This requirement is not applicable for the DODIN Backbone. 

Review the router configuration and determine if filters are bound to the external interfaces to drop IPv6 packets containing a Destination Option header with option type values of 0x05 (Router Alert) or 0xC2 (Jumbo Payload). 

Verify the IPv6 filter has the next header value set to 60, as shown in the example below: 

- show filter ipv6 40

Entry               : 10
Description         : (Not Specified)
Log Id              : n/a
Src. IP             : ::/0
Src. Port           : n/a
Dest. IP            : ::/0
Dest. Port          : n/a
Next Header         : 60

Verify an "Ing IPv6 Flt" has been applied to the interface, as shown in the example below: 

- show router interface "TO-PE2" detail | match "Ingr IPv6 Flt"
Egr IPv6 Flt     : none                 Ingr IPv6 Flt     : 40

If the router is not configured to drop IPv6 packets containing a Destination Option header with invalid option type values, this is a finding.