A company that specializes in e-mail performance is reporting today that 80 percent of all e-mail is being sent by illegitimate or unknown mail servers.

 

According to Return Path’s “Reputation Benchmark Report,” 46 percent of e-mail is being sent by “compromised” hosts, dynamic IP addresses and other non-mail servers that shouldn’t be sending any communications at all.

 

George Bilbrey, the company’s general manager of delivery assurance, said the study quantifies the impact of IP reputation on the deliverability of the messages coming from that IP.

 

“Clearly, e-mail best practices matter,” Bilbrey said. “If you’re sending commercial e-mail from a legitimate mail server, your e-mail has a better chance to reach consumers’ inboxes. Commercial senders need to be vigilant about all aspects of e-mail sending, including infrastructure, list hygiene and the value of their messages to recipients.”

Officials say the study relies on a sample of 2.3 million IPs pulled from the Return Path Reputation Data Network, a cooperative data network that collects and analyzes e-mail data from more than 20 ISPs and other data providers representing more than 100 million mailboxes.

 

For the study, Return Path officials say they removed data from servers that do not have reverse DNS and “are clearly not supposed to be sending e-mail.”

 

“If you factor in the 35 percent of servers with no reverse DNS, the ‘bad’ mail hosts goes even higher with 87 percent of e-mail being sent from mail hosts that should not be sending e-mail,” officials say.

Company officials say they discovered a link between deliverability success rates and the quality of the server that e-mail is sent from.

 

In short, e-mail sent from legitimate e-mail servers averaged 56 percent delivery rates, 20 percent rejection, and 8 percent filtered, according to the company. E-mail sent from servers that were identified as illegitimate had average rejection rates of 60 percent and delivered rates of 23 percent, company officials say.

 

“Illegitimate hosts actually had low filtered rates – slightly less than 1 percent on average,” according to the company. “While this may seem counterintuitive, it actually makes perfect sense – e-mail coming from illegitimate sources is easy to identify and reject. Contrast these rates to e-mail sent from unknown hosts which averaged 45 percent delivery rates, 5 percent filtered rates, and 35 percent rejection rates.”