Traffic that comes into the secondary network interface leaves the instance using the primary network interface. These issues occur because the primary and secondary network interfaces are in the same subnet, and there is one routing table with one gateway.
To avoid asymmetric routing issues, use a single elastic network interface, or place duplicate elastic network interfaces into non-overlapping subnets.Īdding a secondary network interface to a non-Amazon Linux EC2 instance causes traffic flow issues. Use a second elastic network interface only if you can't use a single network interface and you must attach two network interfaces belonging to the same subnet to a single instance. Warning: The use of a second elastic network interface is intended for advanced users.
