NAT gateway metrics and dimensions - Amazon Virtual Private Cloud
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NAT gateway metrics and dimensions

The following metrics are available for your NAT gateways. The description column includes a description of each metrics as well as the units and statistics.

Metric Description
ActiveConnectionCount

The total number of concurrent active TCP connections through the NAT gateway.

A value of zero indicates that there are no active connections through the NAT gateway.

Units: Count

Statistics: The most useful statistic is Max.
BytesInFromDestination

The number of bytes received by the NAT gateway from the destination.

If the value for BytesOutToSource is less than the value for BytesInFromDestination, there might be data loss during NAT gateway processing, or traffic being actively blocked by the NAT gateway.

Units: Bytes

Statistics: The most useful statistic is Sum.
BytesInFromSource

The number of bytes received by the NAT gateway from clients in your VPC.

If the value for BytesOutToDestination is less than the value for BytesInFromSource, there might be data loss during NAT gateway processing.

Units: Bytes

Statistics: The most useful statistic is Sum.
BytesOutToDestination

The number of bytes sent out through the NAT gateway to the destination.

A value greater than zero indicates that there is traffic going to the internet from clients that are behind the NAT gateway. If the value for BytesOutToDestination is less than the value for BytesInFromSource, there might be data loss during NAT gateway processing.

Unit: Bytes

Statistics: The most useful statistic is Sum.
BytesOutToSource

The number of bytes sent through the NAT gateway to the clients in your VPC.

A value greater than zero indicates that there is traffic coming from the internet to clients that are behind the NAT gateway. If the value for BytesOutToSource is less than the value for BytesInFromDestination, there might be data loss during NAT gateway processing, or traffic being actively blocked by the NAT gateway.

Units: Bytes

Statistics: The most useful statistic is Sum.
ConnectionAttemptCount

The number of connection attempts made through the NAT gateway.

If the value for ConnectionEstablishedCount is less than the value for ConnectionAttemptCount, this indicates that clients behind the NAT gateway attempted to establish new connections for which there was no response.

Unit: Count

Statistics: The most useful statistic is Sum.
ConnectionEstablishedCount

The number of connections established through the NAT gateway.

If the value for ConnectionEstablishedCount is less than the value for ConnectionAttemptCount, this indicates that clients behind the NAT gateway attempted to establish new connections for which there was no response.

Unit: Count

Statistics: The most useful statistic is Sum.
ErrorPortAllocation

The number of times the NAT gateway could not allocate a source port.

A value greater than zero indicates that too many concurrent connections are open through the NAT gateway.

Units: Count

Statistics: The most useful statistic is Sum.
IdleTimeoutCount

The number of connections that transitioned from the active state to the idle state. An active connection transitions to idle if it was not closed gracefully and there was no activity for the last 350 seconds.

A value greater than zero indicates that there are connections that have been moved to an idle state. If the value for IdleTimeoutCount increases, it might indicate that clients behind the NAT gateway are re-using stale connections.

Unit: Count

Statistics: The most useful statistic is Sum.
PacketsDropCount

The number of packets dropped by the NAT gateway.

To calculate the number of dropped packets as a percentage of the overall packet traffic, use this formula: PacketsDropCount/(PacketsInFromSource+PacketsInFromDestination)*100. If this value exceeds 0.01 percent of the total traffic on the NAT gateway, there may be an issue with Amazon VPC service. Use the Amazon service health dashboard to identify any issues with the service that may be causing NAT gateways to drop packets.

Units: Count

Statistics: The most useful statistic is Sum.
PacketsInFromDestination

The number of packets received by the NAT gateway from the destination.

If the value for PacketsOutToSource is less than the value for PacketsInFromDestination, there might be data loss during NAT gateway processing, or traffic being actively blocked by the NAT gateway.

Unit: Count

Statistics: The most useful statistic is Sum.
PacketsInFromSource

The number of packets received by the NAT gateway from clients in your VPC.

If the value for PacketsOutToDestination is less than the value for PacketsInFromSource, there might be data loss during NAT gateway processing.

Unit: Count

Statistics: The most useful statistic is Sum.
PacketsOutToDestination

The number of packets sent out through the NAT gateway to the destination.

A value greater than zero indicates that there is traffic going to the internet from clients that are behind the NAT gateway. If the value for PacketsOutToDestination is less than the value for PacketsInFromSource, there might be data loss during NAT gateway processing.

Unit: Count

Statistics: The most useful statistic is Sum.
PacketsOutToSource

The number of packets sent through the NAT gateway to the clients in your VPC.

A value greater than zero indicates that there is traffic coming from the internet to clients that are behind the NAT gateway. If the value for PacketsOutToSource is less than the value for PacketsInFromDestination, there might be data loss during NAT gateway processing, or traffic being actively blocked by the NAT gateway.

Unit: Count

Statistics: The most useful statistic is Sum.
PeakBytesPerSecond

This metric reports the highest 10-second bytes per second average in a given minute.

Units: Count

Statistics: The most useful statistic is Maximum.
PeakPacketsPerSecond

This metric calculates the average packet rate (packets processed per second) every 10 seconds for 60 seconds and then reports the maximum of the six rates (the highest average packet rate).

Units: Count

Statistics: The most useful statistic is Maximum.

To filter the metric data, use the following dimension.

Dimension Description
NatGatewayId Filter the metric data by the NAT gateway ID.