Load Balancer now supports forwarding and processing ICMP messages
to improve the robustness of connection protocols and permit Load Balancer
to receive ICMP fragmentation messages.
Load Balancer will forward an ICMP message based on the following guidelines:
- For ICMP packets that contain headers with IP and TCP/UDP fragments, Load
Balancer will forward to packets to the correct back-end server.
- For ICMP packets that do not contain TCP/UDP fragments, Load Balancer
will forward the packets in a round robin manner.
- For ICMP messages that are for an IPGRE or an IPIP message that Load Balancer
generated, Load Balancer will limit the outbound size appropriately for future
packets.
- If Load Balancer forwards an IP packet, but the time to live (TTL) for
the packet becomes zero when the TTL is decremented, Load Balancer will send
an "ICMP Time Exceeded" message to the client.
- When Load Balancer cannot forward an packet, it will generate an ICMP
message and send the appropriate message back to the client:
- The outbound interface MTU is too small, or you need to use encapsulation.
- Load Balancer cleaned up a connection record. For example, the cluster
and port designation match, but the server is not present.