The ICMPv6 Neighbor Discovery Protocol (NDP) is a set of messages and processes that enable devices to discover and maintain information about neighboring nodes. NDP plays a crucial role in IPv6 networks, facilitating the interaction between devices on the same link.
The Cluster Network Operator (CNO) deploys the iptables implementation of multi-network policy when the `useMultiNetworkPolicy` parameter is set to `true`.
To support multi-network policies in IPv6 networks the Cluster Network Operator deploys the following set of custom rules in every pod affected by a multi-network policy:
`icmpv6-type neighbor-solicitation`:: This rule allows incoming ICMPv6 neighbor solicitation messages, which are part of the neighbor discovery protocol (NDP). These messages help determine the link-layer addresses of neighboring nodes.
`icmpv6-type neighbor-advertisement`:: This rule allows incoming ICMPv6 neighbor advertisement messages, which are part of NDP and provide information about the link-layer address of the sender.
`icmpv6-type router-solicitation`:: This rule permits incoming ICMPv6 router solicitation messages. Hosts use these messages to request router configuration information.
`icmpv6-type router-advertisement`:: This rule allows incoming ICMPv6 router advertisement messages, which give configuration information to hosts.
The rules collectively enable essential ICMPv6 traffic for correct network functioning, including address resolution and router communication in an IPv6 environment. With these rules in place and a multi-network policy denying traffic, applications are not expected to experience connectivity issues.
