If you sent an e-mail directly to a Library of Congress mailbox, your e-mail may have been inadvertently blocked by our spam filter. The Library uses measures that are generally effective against blocking spam. Any approach to filtering, though, results in some legitimate mail, like yours, being lost. The Library continues to monitor the situation to keep spam at a manageable level and minimize the loss of legitimate e-mail. We sincerely apologize for the difficulties this causes you and the intended recipient.

The easiest way to get your e-mail unblocked is to send an e-mail message from the account that generated the blocked message, briefly describing your situation, to unblock@loc.gov. This is a special e-mail address that will receive your message even if it is being blocked to other recipients at the Library.

An information technology security staff member will assist you in being removed from the block list in order to allow your e-mail to reach the Library and other destinations that employ spam-blocking methods similar to ours.

E-mail spam is equivalent to junk mail. It is e-mail that is widely distributed, unsolicited, and usually contains advertising. You didn't ask for it and probably do not want it. It includes: chain letters, pyramid schemes, requests for financial support, and invitations to visit adult web sites. It is essentially free advertising for the spammer; the cost in human and technical resources is borne by the recipient. This and post-anthrax problems with surface mail have led to a huge increase in spam.

In June 2002, the Library adopted a policy to minimize spam and currently employs spam-blocking measures that are consistent with practices employed at the National Institute of Standards and Technology.

Incoming e-mail is blocked if it appears on one of several widely used spam-blocking lists. These lists, referred to as DNS block lists (DNSBLs), are maintained by third-parties and are available to the public. These lists change continually as new spam sources are identified and added and "open relays" are closed and removed. There is also an internal block list of addresses that have been identified as spam sites by Library staff.

"Open relays" are e-mail servers that allow virtually anyone to send e-mail through them. "Open relays" are commonly used by spammers to mask their origin, since e-mail servers look at the last transmission point. A message will appear to have come from an "open relay" if that was its last hop rather than from the original sender. This often explains how legitimate e-mail gets blocked along with spam. Smaller organizations and companies may not have the technical resources to know that they are running "open relays" and thus will have e-mail blocked by the Library as well as other organizations that block spam.

Anyone sending e-mail to the Library will be notified with the following by return e-mail if a message is blocked:

"Mail could not be delivered (code).
See http://www.loc.gov/homepage/faq-spam.html
or e-mail unblock@loc.gov for help."

In some cases you may receive a different message, which means the Library of Congress message above was intercepted and another message substituted by an intermediate server. In the rare event that the sender does not receive notification, it means the intermediate server simply removed the Library of Congress notification.

The blocked message is not saved at the Library.

Usually not. You'll have to work together with your e-mail service provider to get your service removed from the spam-block lists. Here's how it works:

1) Find out the IP (Internet Protocol) address of your e-mail server. You may have to get this information from your Internet Service Provider (ISP).

2) Determine the DNSBLs (spam-blocking lists) that list your e-mail server by checking their Web sites and entering your e-mail server IP address. Suggested sites to check: http://openrbl.org/ or http://moensted.dk/spam/.

3) If your server is listed as "open relay," your e-mail service provider must take steps to secure it. Ask your service provider to follow the step-by-step instructions that can be found at http://mail-abuse.org/tsi/ar-fix.html and at http://rbls.org/.

4) Ask your e-mail service provider to request that your service be retested and delisted from each DSNBL that lists your server.