Certain SMTP proxies implement TCP connection management (otherwise known as flow control), which can help to reduce damage to downstream mail servers resulting from spikes in TCP traffic from malicious SMTP clients. TCP connection management in the context of SMTP typically involves bandwidth throttling and/or introducing delays in SMTP command responses (this is also known as tarpitting). When slowed down, certain malicious sources of SMTP traffic such as spam bots tend to give up rather than continuing to deliver a full email message.