Passive Spam Block List

PSBL

News

List query

Why did my IP address get listed?

Your IP address got listed because it delivered an email to one of the spamtrap addresses that feed PSBL.

Does that mean my system sent you spam?

99% of the mail coming into the spamtraps is spam. PSBL's scripts try to filter bounces and virusses out of the remaining 1%. This means that almost all IP addresses listed in the PSBL are there because they really sent spam.

However, the vast majority of spam is sent from virus and malware infested end-user systems and the amount of email received from actual mail servers is very small. Keeping this in mind, if your mail server got listed on the PSBL it may well be a false positive. The evidence pages should be able to tell you more.

But my system isn't a mail server...

In that case the mail I got is almost certainly spam. Usually via a virus or trojan horse that installed itself onto your computer through one of the various security holes that are always available on end-user systems. Please get some recent anti-virus software and desinfect your system.

Note that if you have a dynamic IP address, it is possible that the user who had the address before you was sending out the spam. It is still a good idea to use recent anti-virus software, though.

Can I remove my IP address from PSBL?

Yes, you can. Just fill in the IP address in the form below and click your way through the automated removal system. The IP address should be gone from the DNS servers within half an hour.

You will also want to figure out why the IP address got listed, so you can fix the problem and make sure you do not get listed again in the future.

How else can IP addresses be removed from PSBL?

After an IP address has not sent anything to to the spamtraps for a few weeks, it is automatically expired from the database. This automatic expiry is by far the normal way for IP addresses to get removed from the list.

Manual removal, using the form above, appears to happen for less than 1% of PSBL's IP addresses. The other 99% are probably spam zombies that never send out legitimate email directly.

What software does PSBL use?

PSBL runs on Spamikaze, a free software package specifically written to make it easy for mail server admins to run their own DNSBL.

Could you give me the headers of the email that caused a listing?

The evidence CGI script fetches any spamtrap mail that is still in the archive. Currently PSBL gets around half a million spamtrap emails per day and has 14GB of news spool to archive spams, which should be good for around one week.

That is my IP address, but the headers are all strange. Was it forged?

PSBL lists the IP address that connected to the PSBL mail server, which means that the spam really came from your IP address.

However, the evidence CGI script obfuscates the headers to prevent spammers from listwashing (removing spamtraps from their lists). Usually this does not matter, since most spam is sent directly from PCs that got infected with spam trojans, and not through mail servers. If the listed IP address happens to be your mail server, does it perhaps act as a firewall for an infected PC?

I run a high volume mail server, with anti-spam measures...

PSBL uses the DNSWL whitelist to exclude known good mail servers from being listed. If your mail server is not whitelisted yet, please fill out this dnswl.org form.

Update: on Jan 10 2009, PSBL has started only whitelisting IP addresses in the classes DNSWL_LOW, DNSWL_MED and DNSWL_HIGH. DNSWL_NONE appears to contain many IP addresses that were delisted from the higher classes due to the sending of too much spam. This is an experimental policy change, which may be reverted if it does not work out.

But my mail is CAN-SPAM compliant and perfectly legal!

PSBL is CAN-BLOCK compliant. ;)

If you send email to harvested email addresses, or email addresses of other dubious origins, you run the risk of being listed on many DNSBLs, including PSBL. In short, while you might have the right to send out certain email, nobody has any obligation to receive it, so you might want to make sure you only send email to people who really want it.

But that's not spam! Don't you read your spamtrap mail?

PSBL gets hundreds of thousands of spamtrap emails each day, or multiple per second (see the latest events). No human can read such an amount of email, so I'm not even trying. Instead, I rely on a set of regular expressions to filter out email which is not spam. If you see a non-spam email listed on the evidence page, please contact me so I can improve the software.

If you need more details on why your server got listed, or you think the Spamikaze software made a mistake, feel free to send me email at psbl(at)surriel(dot)com and I'll see what I can do. Mail server logs are generally available.