Gmail blocked by anti-spam vendors

It all began when Google's bot-busting CAPTCHA for Gmail was defeated sometime in February. According to sources around the anti-spam industry, the result has been a marked increase in spam originating from Gmail SMTP servers. Some say the spam increase started even earlier, but all claim this is a serious problem.

 

A support analyst with MessageLabs, a major provider of software-as-a-service anti-spam filtering, told that "were able to relay spams appearing to come from Googlemail's IP addresses. This has caused many IPs of theirs to appear to be sources of spam." For their customers, this means a decrease in performance. "We have a traffic-shaping system that throttles IPs that we believe to appear to be a source of spam. The result is that for the past couple of days we have been seeing issues like this with Gmail," the analyst concluded.

 

When spam is sent out over a Gmail relay, that relay can sometimes get completely blocked, causing problems for thousands of legitimate Gmail users. MessageLabs then has to play whack-a-mole, trying to throttle only the SMTP relays that are spamming.

 

The damage currently appears limited to select SaaS filtering solutions, such as MessageLabs and Antigen. Yet, a source at another anti-spam company stated that Google can expect more problems if the CAPTCHA crack cannot be stopped.