Navigation Bar

Anti-spam Measures

As you are probably aware, unsolicited commercial e-mail, a.k.a., spam, has become a significant problem on the Internet in recent months. To combat this problem we have become more draconian in our e-mail rejection policies — we blacklist sites on the Internet that are known to be originators of spam. We also use anti-virus software to reject any e-mail that contains known viruses. And we use SPF information to verify the orgin of email. Through these measures, many of our users have reported a dramatic reduction in the volume of spam that they receive.

How to get on our blacklist
We use various blacklists (see below) to limit e-mail accepted by our mail server. Incoming e-mail from an Internet host listed on one of these blacklists will be rejected and returned to the sender. If we discover e-mail with spam content, then we report the abuse and/or blacklist the originating site. We also have a set of local rules that our mail server checks before accepting e-mail. Our local blacklist consists of:

• Any site that does not have both forward and reverse mappings between its host name and IP address.
Solution: have your ISP fix it and/or register your computer.
• Any site that lies about who it is in the reverse host name lookup (i.e., if the remote mail server is diablo4.dnswithus.net but the IP name lookup says it's mindcraft.com)
Solution: Don't lie.
• Home dialup or DSL Internet connections.
Workaround: send outgoing email via your ISP.
• Sites that send out spam (that isn't caught by other blacklists).
Solution: send email to antispam@cgl.ucsf.edu when you've stopped sending spam.
• Sites that reject standard e-mail reporting errors.
Solution: fix your mail software to follow RFC 1123 error messages (i.e., accept MAIL FROM:<>).
We also whitelist sites that are known not to originate spam using the same technology (e.g., some sites within UCSF that sometimes do bulk e-mailing).
How to get off our blacklist

Or what to do when you received an error message like:
550 Access denied, send email to antispam@cgl.ucsf.edu if in error

If your mail server is listed in our local blacklist incorrectly, send e-mail to antispam@cgl.ucsf.edu. You will receive personal attention. If we've made a mistake in listing your server, then we'd be happy to remove it from our blacklist.
Blacklists we use in addition to our local one
If we reject e-mail due to a match in a blacklist, we report which blacklist it was and provide a URL to use for discovering more about that particular blacklist. The exact set of blacklists we use is subject to change, but currently we use the Open Relay Database (ORDB), the Spamhaus blacklist, the Spam Cop blacklist, and our local blacklist. (See the spam database list for some other possible blacklists.)
SPF
SPF is an emerging Internet technology where the Internet addresses that can legally send email for a domain are published in the DNS.
Articles and other information about SPF:

SPF: Sender Policy Framework
PC Magazine article: Stopping Spam
Infoworld article: Sender ID e-mail spec submitted to standards body
eWeek article: New Anti-spam Initiative Gaining Traction
Linux Journal article: SPF Overview
Linux Journal article: SPF, MTAs, and SRS

Definitions

blacklist
Email and IP addresses that we never wish to receive emails from.
DNS
The Domain Name System, an Internet-wide database that contains information about domain names, such as their IP address.
IP address
Internet Protocol address: an unique identifier assigned to each site on the Internet for communicating with other sites.
ISP
Internet Service Provider: a business (school) that provides other businesses or individuals access to the Internet.
whitelist
Email and IP addresses that we always wish to receive emails from.