Performance Monitor counters for the SMTP Server object include the following.
| Counter | Counter Definition |
| Bytes Sent Total | The total number of bytes sent by Microsoft SMTP Service. |
| Bytes Sent/sec | The rate at which bytes are sent by Microsoft SMTP Service. |
| Bytes Received Total | The total number of bytes received by Microsoft SMTP Service. |
| Bytes Received/sec | The rate at which bytes are received by Microsoft SMTP Service. |
| Bytes Total | The total number of bytes sent by Microsoft SMTP Service. |
| Bytes Total/sec | The sum of Bytes Sent/sec and Bytes Received/sec. This is the total rate at which bytes are transferred by Microsoft SMTP Service. |
| Message Bytes Sent Total | The total number of bytes containing message text (also known as mail data) sent by Microsoft SMTP Service. |
| Message Bytes Sent/sec | The rate at which bytes containing message text (also known as mail data) are sent by Microsoft SMTP Service. |
| Message Bytes Received Total | The total number of bytes containing message text (also known as mail data) received by Microsoft SMTP Service. |
| Message Bytes Received/sec | The rate at which bytes containing message text (also known as mail data) are received by Microsoft SMTP Service. |
| Message Bytes Total | The sum of Message Bytes Sent Total and Message Bytes Received Total. This is the total number of bytes transferred in messages by Microsoft SMTP Service. |
| Message Bytes Total/sec | The sum of Message Bytes Sent/sec and Message Bytes Received/sec. This is the total rate of bytes transferred in messages by Microsoft SMTP Service. |
| Messages Received Total | The total number of messages accepted by Microsoft SMTP Service. |
| Message Received/sec | The rate at which inbound messages are being accepted by Microsoft SMTP Service. This includes messages that generate NDRs. |
| Avg Recipients/msg Received | The average number of recipients per message received by Microsoft SMTP Service. This includes messages that generate NDRs. |
| % Recipients Local |
The percentage of messages delivered to local recipients, as defined in the Routing table. Note This counter is not relevant for this version of Microsoft SMTP Service. |
| % Recipients Remote |
The percentage of recipients that will be sent to remote servers or clients, as defined in the Routing table. Note This counter is not relevant for this version of Microsoft SMTP Service. |
| Messages Refused for Size | The total number of messages rejected because their message bytes would take up too much disk space. The maximum memory allocation per message can be specified in Internet Service Manager. |
| Messages Refused for Address Objects | The total number of messages refused because Windows NT cannot allocate any more disk space. Address objects are used by the SMTP Server computer to represent addresses in memory; by default, there are 100,000 objects. |
| Messages Refused for Mail Objects | The total number of messages refused because Windows NT cannot allocate any more disk space. A mail object is used by Windows NT to represent messages in memory; by default, there are 100,000 objects. |
| Messages Delivered Total |
The total number of messages delivered to local mailboxes. Note This counter is not relevant for this version of Microsoft SMTP Service. |
| Messages Delivered/sec |
The rate that messages are delivered to local mailboxes. Note: This counter is not relevant for this version of Microsoft SMTP Service. |
| Message Delivery Retries |
The total number of local deliveries that were put in the local retry queue. You can limit the number of retries per message in Internet Service Manager. Note This counter is not relevant for this version of Microsoft SMTP Service. |
| Avg Retries/msg Delivered |
The average number of retries per local delivery. This is equal to Message Delivery Retries divided by Messages Delivered Total.
Note This counter is not relevant for this version of Microsoft SMTP Service. |
| NDR's Generated | The number of NDRs that have been generated. |
| Local Queue Length | The number of messages in the local queue. The normal value is 0. If this counter is > 0, the server is receiving more messages than it can process. |
| Local Retry Queue Length | The number of messages currently in the local retry queue. |
| Remote Retry Queue Length | The number of messages currently in the remote retry queue. |
| Number of Mail Files Open | The number of mail files with open handles. All Windows NT objects have ôhandlesö that can be open or closed. If an objectÆs handle is open, the object is currently available to Windows NT. Too many open handles overwhelm Windows NT resources. |
| Number of Queue Files Open | The number of address files with open handles. When performance is optimum, few files are queued. So when this counter continues to increase without leveling off, a performance problem is indicated. |
| Messages Sent Total | The total number of messages sent to remote servers. |
| Messages Sent/sec | The rate at which messages are being sent to remote servers. |
| Message Send Retries | The total number of times Microsoft SMTP Service failed to send messages. |
| Messages Retrieved Total | The total number of messages taken from the Pickup directory. |
| Messages Retrieved/sec | The rate that messages are taken from the Pickup directory. |
| Avg Retries/msg Sent | The average number of retries per outbound message sent. |
| Avg Recipients/msg Sent | The average number of recipients per outbound messages sent. |
| Remote Queue Length | The number of messages in the remote queue. The normal value is 0. If this counter is > 0, either or both of the following can be occurring: the server is receiving more messages than it can process, or outbound connections are slow. |
| Directory Drops Total | The number of messages received and placed in the Drop directory. You can designate a Drop directory limit in Internet Service Manager. |
| Directory Drops/sec | The rate at which messages are received and placed in the Drop directory. |
| Directory Pickup Queue Length | The number of messages currently in the Pickup directory. |
| ETRN Messages Total |
The number of messages in the ETRN domain. Note This counter is not relevant for this version of Microsoft SMTP Service. |
| ETRN Messages/sec |
The rate at which messages are placed in the ETRN domain. Note This counter is not relevant for this version of Microsoft SMTP Service. |
| Routing Table Lookups Total | The total number of Domain Routing table lookups. The domain routing table maps one domain name to another. |
| Routing Table Lookups/sec | The rate at which Domain Routing table lookups occur per second. |
| DNS Queries Total | The total number of DNS lookups. The DNS server maps an IP address to domain names presented to it from Microsoft SMTP Service. |
| DNS Queries/sec | The rate of DNS lookups. |
| Inbound Connections Total | The total number of inbound connections. |
| Inbound Connections Current | The number of connections currently inbound. The normal value is greater than zero. A value of zero for an extended time might indicate that there are network problems in reaching Microsoft SMTP Service. |
| Outbound Connections Total | The total number of outbound connections attempted. |
| Outbound Connections Current | The number of connections currently outbound. |
| Outbound Connections Refused | The number of outbound connection attempts refused by remote sites. |
| Total Connection Errors | The total number of SMTP protocol errors from attempts at inbound connection. |
| Connection Errors/sec | The number of connection errors per second. |