seems that there are installs of the smtp-auth patch to qmail that accept anything as a user name and password and thus allow you to connect. http://marc.theaimsgroup.com/?l=qmail&m=105452174430616&w=2 is one URL that talks about this. There has been an increase is what appears to be qmail based open-relays over the last 5 days. Each of these servers pass the normal suite of open-relay tests. Spammers are scanning for SMTP-AUTH and STARTTLS based mail servers that may be misconfigured. Then using them to send out their trash. Some early docs on setting up qmail based smtp-auth systems had the config infor incorrect. This leads to /usr/bin/true being used as the password checker. :(
From an operational perspective, I suspect we will see more SMTP scans
The basic test (see URL above) should get incorporated into various open-relay testing scripts. cheers john brown chagres technologies, inc