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Best Practices

How MailChannels and Sendmail Differ in Their Approach

By MailChannels | 3 minute read

How MailChannels And Sendmail Differ In Their Approach

Spam is an unwelcome guest in our inboxes, and fighting it requires smart strategies. MailChannels has a unique approach with its TrafficControl product. Instead of just blocking spam, it slows down the conversation with the spammer, mimicking a sluggish connection. Imagine a spammer trying to send a 20kB email but crawling at a snail’s pace of 15 bytes per second. It’s like waiting in line for 20 minutes only to be told to come back later – most spammers would rather give up!

Now, you might wonder, “Doesn’t Sendmail do something similar?” Well, not quite. Sendmail takes a different route by focusing on controlling the rate at which connections are made, rather than the speed of the conversation. It’s like having a bouncer at the door of a club, limiting the number of people who can enter per minute. If things get too crowded, Sendmail puts up a “Temporarily Unavailable” sign.

Sendmail has a few tools in its kit:

  • Ratecontrol: This limits the number of connections a server can make in a minute. It’s handy during a single-machine attack but less so against a coordinated assault from multiple sources.
  • Conncontrol: This prevents an attacker from slowly building up a swarm of connections, setting a cap on how many connections a host can have at once.
  • ConnectionRateThrottle: Similar to ratecontrol, but it applies a global limit, which is more effective against distributed attacks.
  • Greet_pause: This adds a small delay before the server greets the sender. If the sender jumps the gun and sends commands before the greeting, Sendmail knows something’s fishy.

Both MailChannels and Sendmail have their strengths in battling spam, but they tackle the problem from different angles. MailChannels slows down the conversation, making it tedious for spammers, while Sendmail acts as a gatekeeper, controlling the flow of incoming connections. Understanding these differences can help system administrators choose the right tool for their needs and keep their inboxes cleaner and more secure.


What is the main difference between MailChannels TrafficControl and Sendmail in combating spam?

MailChannels TrafficControl focuses on slowing down the SMTP conversation with spammers, making it time-consuming and less appealing for them to send spam. On the other hand, Sendmail concentrates on limiting the rate and number of connections to the server, acting as a gatekeeper to prevent spam attacks.

How does Sendmail’s ratecontrol feature work?

Sendmail’s ratecontrol feature limits the number of connections a server can make in a minute. This is particularly effective against attacks from a single machine but less so against distributed attacks from multiple sources.

What is the purpose of Sendmail’s greet_pause feature?

The greet_pause feature adds a delay before the server greets the sender. If the sender sends commands before receiving the greeting, Sendmail recognizes this as suspicious behavior, indicative of a potential spam attack.

Can Sendmail’s conncontrol feature prevent all types of spam attacks?

Conncontrol is designed to prevent an attacker from slowly building up a large number of connections. It sets a cap on how many connections a host can have at once, which is effective against certain types of spam attacks but may not be foolproof against all strategies used by spammers.

Is one method better than the other in reducing spam?

Both methods have their strengths and are effective in different scenarios. MailChannels TrafficControl is more about discouraging spammers by slowing down the conversation, while Sendmail focuses on controlling access to the server. The choice between the two depends on the specific needs and circumstances of the server being protected.

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