3. Deprecation of RH0

An IPv6 node that receives a packet with a destination address assigned to it and that contains an RH0 extension header MUST NOT execute the algorithm specified in the latter part of Section 4.4 of [RFC 2460] for RH0. Instead, such packets MUST be processed according to the requirements specified in Section 4.4 of [RFC 2460] for a datagram that includes an unrecognized Routing Type value, namely:

• If Segments Left is zero, the node must ignore the Routing header and proceed to process the next header in the packet, whose type is identified by the Next Header field in the Routing header.

• If Segments Left is non-zero, the node must discard the packet and send an ICMP Parameter Problem, Code 0, message to the packet's Source Address, pointing to the unrecognized Routing Type.

IPv6 nodes are no longer required to implement RH0 in any way.

3.1. Host Requirements

An IPv6 host MUST NOT send packets containing RH0 extension headers.

An IPv6 host that receives a packet containing an RH0 extension header MUST process it according to the requirements in Section 3 above.

3.2. Router Requirements

An IPv6 router MUST NOT send packets containing RH0 extension headers.

An IPv6 router that receives a packet containing an RH0 extension header MUST process it according to the requirements in Section 3 above.

An IPv6 router SHOULD have the ability to be configured to drop all packets containing RH0 extension headers.

3.3. Firewall Requirements

It is to be expected that it will be appropriate for most firewalls to drop packets containing RH0 extension headers by default.