Post #9 on Why Spam Filters Suck “trickle blog” series

Real World Scenarios

Despite all the money invested into anti-spam solutions, spam volume continues to rise. Yes, spamming is an arms race. But the real race is one of sheer volume.

Spammers respond to difficulty by simply sending more spam. Better filtering? Send more to improve numbers getting through. Spamming not profitable enough? Send more spam. Users not interested? Send more variety. With botnets, spammers have a highly scalable delivery infrastructure and are not limited by resources. Unfortunately, it’s the receiver of spam that bears the cost of that volume.

The problem is more than just the annoyance of spam. Spam is a big cost to organizations. High spam volumes lead to delays in email delivery and significant over-capacity to handle spikes in volume. Email providers know customers are very sensitive to any delays in the receipt of important email, and any service disruptions by a failure to handle loads can have immediate complaints and ongoing financial impacts.

Delays in email delivery caused by high spam traffic divert IT attention to chase spam.

Ongoing IT workload costs likely dwarf one-time capital expenditures for new systems.
Adding capacity in chunks with each budget period makes it difficult to know if it’s too little or too much to scale capacity to meet volumes.

Traffic shaping reduce IT infrastructure and support costs because it removes more spam at the connection level than any other approach.

One of the Fortune 500 companies MailChannels works with has implemented traffic shaping solely to get their infrastructure costs under control. They were being flooded with spam and as a result legitimate email was being crowded out by the spam resulting in delivert delays of hours at a time. Their spam filters were getting rid of it so the end users didn’t see it but the servers were doing all they could to process backlogged traffic. The company couldn’t accept any more mail, they were are there limit in terms of concurrent SMTP connections and were at a loss to come up with a good strategy for dealing with all the spam.

They were using all the blacklists they could find, but even though the blacklists got rid of 50 to 70 percent of spam coming from known spam sources, the spam that got through was significant enough to be a very serious problem for end users and administrators trying to keep the email service flowing.

Implementing email traffic shaping in front of their servers dramatically dropped spam from 70 percent of all processed traffic down to 20 percent overnight as a result they turned off 4 of the 6 servers they were using to handle all inbound mail. More importantly, they no longer needed to waste time maintaining content filters, adding more servers or experiencing slow SMTP responses.

There are limitations with every anti-spam technology. While filtering is an effective at separating spam from email, it is only one layer in a multi-tiered anti-spam architecture designed to leverage various technologies suited to each task. Applying traffic shaping at the network edge ensures legitimate senders get excellent quality of service and their mail flows quickly, while spammers are given very poor quality of service and their mail is not allowed into your network.

NEXT: Post #10 Challenges of Traffic Shaping
PREVIOUS: Post #8 Dealing Spammers a Blow