Sendmail, the Flexible Mail Solution

In 1981, Eric Allman wrote the software for the mail transfer agent (MTA) that eventually developed into Sendmail. Today, Emeryville, Calif.-based Sendmail, Inc. handles the corporate mail server part of the continuing Sendmail endeavor.

The most important issue for mail servers at the moment is spam, and Sendmail has just released Mailstream Anti-spam Solution 2.0 (MAS 2.0). Jon Ore, director of product marketing for the Mailcenter product line, says that the product isolates mail control at the edge of the network.

“ISPs can throttle email, and they can also control email exiting the network,” says Ore.

He adds that it’s more important than ever to be tracking what users are doing. “ISPs may now get subpoenaed in spam cases. ISPs have to identify and control spammers.”

The new solution includes parts that are licensed from anti-spam specialists. “We evaluated over 40 anti-spam solutions,” says Ore.

Given the company’s knowledge of Sendmail, it should be no surprise that the company’s software works well with Sendmail’s Milter API. “Some companies use an inefficient sandwich configuration,” says Ore. “Trend Micro, for example, does not write management filters to the Milter API. Instead, they pass mail to the MTA, then off to the Trend Micro MTA, and then to another Sendmail MTA for downstream processing.”

Placing the anti-spam engine inside the mail flow is better, says Ore. “It’s a really really efficient use of routing and bandwidth, and it reduces the number of MTAs that customers have to buy.”

In addition to undisclosed licensed technology, Mailcenter subscribes to the Cloudmark network’s gateway solution, but the company is not deploying Cloudmark’s cliend side solution.

Sendmail, Inc. added some of its own software. “We use Bayesian techniques and heuristics to assign a probability that a particular mail is spam. We also allow the administrator to set different quarantine levels for different users.”

Users can also set preferences, if they wish. They can set, for themselves, the threshold at which the filter defines a message as spam. They can also block unwanted messages. “If a user calls an ISP and says they signed up for a newsletter and cannot unsubscribe, that’s not spam as defined but the user can choose to block it as spam. Users can manage their own whitelists and blacklists.”

Some anti-spam vendors have told ISP-Planet that some ISPs want to be able to allow their subscribers to opt into some kinds of spam. Says Ore, “ISPs can set preferences for groups of users who want to opt into spam. They could set groups by sender type or subject type.”

Flexibility is key
Sendmail is particularly attractive to ISPs that already have certain network components in place and don’t want to change them, but need a better mail server.

Ore says, “Mailcenter can thwart DoS and harvesting attacks. If a domain is making too many connections to you, you can throttle them to one connection.”

He adds that Mailcenter handles emergencies ISPs may not have foreseen. “After the power outage [in the Northeast this year”, when the mail servers came back up, they were flooded. Mailcenter is designed to mitigate that by accepting a certain number of connections and queuing the rest at the sender’s end.”

One satisfied customer is the eponymous Ellijay Telephone Company, based in the North Georgia town of the same name. The company was founded in 1903 and now offers a complete suite of telephone, Internet, cable television, and telephone directory services.

“Sendmail 2.0 has been great,” says Brian Elliot, speaking on cell phone from a home where he had just completed an installation. “Their service team came out.”

The upgrade has allowed him to use a cheaper operating system. “The older version was running on SUN platform. We’re on RedHat now. We were paying about $10,000 per year for support, and had all our mail except Webmail on one box. Now we’re running five servers and support’s cheaper than it was before.”

“With the supported we’ve needed out of RedHat they’ve done real well with us too,” he adds.

Everything except the anti-spam solution is Sendmail. “We’re using the SAM server for the backend. We’re using the Sendmail MTA. Our Webmail is Sendmail.”

For anti-spam, the company uses Ironmail from Ciphertrust. Elliot says that a recent upgrade to Ironmail actually increased the amount of spam getting through the filter, but, “we’re working through that with them.”

For Elliot, the most significant addition in Sendmail 2.0 is the Webmail upgrade. “We had some zombie processes. Webmail would be locked up, and you’d get an SMS attachment error when you tried to log on. We would have to reboot the server twice a day. They got us to upgrade to the beta and then the final version and now we don’t have to touch the box.”

So that’s the most important feature of Sendmail—flexibility to choose the mail server elements that work for you.

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