Incorrect rejection messages

At least one ESP and Spamhaus are currently investigating bounce messages at a couple ISPs incorrectly pointing to Spamhaus as the reason for the block. The bounce messages are taking the form:

smtp; 554 p3plibsmtp03-07.prod.phx3.secureserver.net bizsmtp IB105. Connection refused. 192.0.2.24 is
listed on the Exploits Block List (XBL) <http://www.spamhaus.org/query/ip/192.0.2.24> Please visit http://www.spamhaus.org/xbl/ for more information.
smtp; 553 5.7.1 [BL21] Connections will not be accepted from 192.0.2.59 because the IP is Spamhaus’s list; see http://postmaster.yahoo.com/550-bl23.html
smtp; 553 5.7.1 [BL21] Connections will not be accepted from 192.0.2.136, because the ip is in
Spamhaus’s list; see http://postmaster.yahoo.com/550-bl23.html

The IPs involved are not listed on any of the Spamhaus lists. It looks like there’s some corruption somewhere. I’ve heard about this from a couple different places, so if it’s happening to you it’s not just you. It’s also being addressed by people who can fix it.

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Holiday mailing advice from mailbox providers

Christine Borgia has a post on the Return Path blog where she interviews a number of different groups (spamfilters, DNSBLs, mailbox providers) about their filtering strategy for the holidays. Overall, no one changes their filtering during the Holiday Mailing Season. On the other hand, many marketers do change their marketing strategies in ways that trigger more filtering and blocking.
The take home message? Pay attention to what is being sent and who it is being sent to. This is nothing new, but many marketers seem to forget it in the effort to get into their customers’ inboxes.

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IP reputation and email delivery

IP reputation is a measure of how much wanted mail a particular IP address sends.  This wanted mail is measured as a portion of the total email sent from that IP. Initially IP reputation was really the be all and end all of reputation, there was no real good way to authenticate a domain or a from address. Many ISPs built complex IP reputation models to evaluate mail based on the IP that sent the mail.
These IP reputation models were the best we had, but there were a lot of ways for spammers to game the system. Some spammers would create lots of accounts at ISPs and use them to open and interact with mail. Other spammers would trickle their mail out over hundreds or thousands of IPs in the hopes of diluting the badness enough to get to the inbox. Through it all they kept trying to get mail out through reputable ESPs, either by posing as legitimate customers or compromising servers.
These things worked for a while, but the ISPs started looking harder at the recipient pool in order to figure out if the interactions were real or not. They started looking at the total amount of identical mail coming from multiple IP addresses. The ISPs couldn’t rely on IP reputation so they started to dig down and get into content based filtering.
As the ISPs got better at identifying content and filtering on factors other than source IP, the importance of the IP address on inbox delivery changed. No longer was it good enough to have a high reputation IP sending mail.
These days your IP reputation dictates how fast you can send mail to a particular ISP. But a high reputation IP isn’t sufficient to get all the mail in the inbox. It’s really content that drives the inbox / bulk folder decisions these days.
 
Generally IPs that the ISP has not seen email traffic from before start out with a slight negative reputation. This is because most new IPs are actually infected machines. The negative reputation translates to rate limiting. The rate limiting minimizes people getting spam while the ISP works out if this is a real sender or a spammer.
Some ISPs put mail in the inbox and bulk foldering during the whitelisting process. In this case what they’re doing is seeing if your recipients care enough about your mail to look for it in the bulk folder. If they do, and they mark the mail as “not spam” then this feeds back to the sender reputation and the IP reputation.
If you’re seeing a lot of bulk foldering of mail, it’s unlikely there’s anything IP reputation based to do. Instead of worrying about IP reputation, focus instead on the content of the mail and see what you may need to do to improve the reputation of the domains and URLs (or landing pages) in the emails.

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Abuse it and lose it

Last week I blogged about the changes at ISPs that make “ISP Relations” harder for many senders. But it’s not just ISPs that are making it a little more difficult to get answers to questions, some spam filtering companies are pulling back on offering support to senders.
For instance, Cloudmark sent out an email to some ESPs late last week informing them that Cloudmark was changing their sender support policies. It’s not that they’re overwhelmed with delisting requests, but rather that many ESPs are asking for specific data about why the mail was blocked. In December, Spamcop informed some ESPs that they would stop providing data to those ESPs about specific blocks and spam trap hits.
These decisions make it harder for ESPs to identify specific customers and lists causing them to get blocked. But I understand why the filtering companies have had to take such a radical step.
Support for senders by filtering companies is a side issue. Their customers are the users of the filtering service and support teams are there to help paying customers. Many of the folks at the filtering companies are good people, though, and they’re willing to help blocked senders and ESPs to figure out the problem.
For them, providing information that helps a company clean up is a win. If an ESP has a spamming customer and the information from the filtering company is helping the ESP force the customer to stop spamming that’s a win and that’s why the filtering companies started providing that data to ESPs.
Unfortunately, there are people who take advantage of the filtering companies. I have dozens of stories about how people are taking advantage of the filtering companies. I won’t share specifics, but the summary is that some people and ESPs ask for the same data over and over and over again. The filtering company rep, in an effort to be helpful and improve the overall email ecosystem, answers their questions and sends the data. In some cases, the ESP acts on the data, the mail stream improves and everyone is happy (except maybe the spammer). In other cases, though, the filtering company sees no change in the mail stream. All the filtering company person gets is yet another request for the same data they sent yesterday.
Repetition is tedious. Repetition is frustrating. Repetition is disheartening. Repetition is annoying.
What we’re seeing from both Spamcop and Cloudmark is the logical result from their reps being tired of dealing with ESPs that aren’t visibly fixing their customer spam problems. Both companies are sending some ESPs to the back of the line when it comes to handling information requests, whether or not those ESPs have actually been part of the problem previously.
The Cloudmark letter makes it clear what they’re frustrated about.

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