This won't work as advertised, in general. Apparantly, CAEM attempts to overflow the initial Received: line by sending a string of garbage to the mail server in place of the hostname (part of the HELO/EHLO command). Since the server adds the connection details to this identity string, the idea is the overlong hostname will overflow the string and prevent the server from logging the IP address in the first Received: line. Most servers won't be caught out by this, especially sendmail, postfix, and exim. Others that are may simply crash instead. The Received: line gives me your IP address, and this is all that an network abuse department flak would need to trace the connection to a particular user. A "whois" program will tell me who owns the netblock so I can find an abuse contact. I can get the information with a subpoena, or the abuse department will usually terminate the account--subject to the particular terms of service--so I don't need it. A private user can sometimes do the same, by scanning USENET groups for postings containing the same IP address posted at roughly the same time (re: NNTP-Posting-* headers), or similarly looking for other non-anonymouse emails sent to archived lists. Google is great for both techniques. As an aside, I know how this works because I used to be an email and usenet administrator for a large global ISP; part of my work there involved *creating* an abuse department from scratch. NOTE THAT THIS IS NOT A SUBSTITUTE FOR AN ANONYMOUS REMAILING SERVICE. Anonymous remailers don't obscure the initial Received: header, they *eliminate* it by *remailing* the email--hence the name. This creates a new initial Received: header pointing to the remailer, and the original is discarded. Remailers keep no logs, so even the connection data stored in the log isn't available, even under subpoena. In short, this provides no real anonymity,