SMTP Performance Trends

SMTP performance trends can be interesting when spam filters are involved. In this example, the server validates the client IP address against a number of DNS blacklists before permitting the connection.

Hence we see a large degree of volatility in the time taken to establish a connection, whilst the SMTP server waits for responses to its' DNS queries.

SMTP Connect Time
Time taken to establish a TCP (and optionally TLS/SSL) connection to the target SMTP server.

Email verification
Time taken to complete an SMTP conversion with the target server, in order to verify the supplied email address.

Data for this graph is collected by the SMTP Monitoring Sensor.

Performance Graphs