I'm on a blocklist! HELP!

Recently, an abuse desk rep asked what to do when customers were complaining about being assigned an IP address located on a blocklist. Because not every blocklist actually affects mail delivery it’s helpful to identify if the listing is causing a problem before diving in and trying to resolve the issue.

  1. Find out whether mail is actually being blocked, or whether the customer just went to one of the jumbo economy blacklist checker sites.
  2. If no mail is being blocked, it’s not an issue.
  3. If mail is being deferred (Yahoo…) it’s not the same issue as being blocked, and likely isn’t worth pursuing.
  4. If mail is being blocked, don’t take the customers word for why. If they got an email rejected by, say, Earthlink for some reason and then went to the blacklist checker and discovered that they’re listed on FIVETEN, they might grab onto that listing like a rabid terrier when it’s really an irrelevant rathole.
  5. Start with the rejection message. If it has a URL in it, that’s all you need to start with.
  6. If not, see if it’s consistent – does test mail get rejected. If not, it’s either a transient issue or it’s a content-based block rather than an IP based block, and hence not your problem.
  7. If there’s no URL in the rejection, contact the entity that blocked the mail, perhaps.
  8. Make a good judgement call about whether it’s worth caring. If it’s just one guy in his Mom’s basement blocking mail then it’s not worth the time or energy to care about the issue.
  9. If this is really business-critical for the customer then they should talk to a decent consultant rather than relying on their abuse desk for assistance.

Related Posts

Sender complaints about spamfiltering

JD posed a question in my post about Postini and trying to sort out a customer getting marked as spam by their filtering mechanism and I think it bears more discussion than can be done in comments.

Read More

Greylisting: that which Yahoo does not do

Over the last couple days multiple people have asserted to me that Yahoo is greylisting mail. The fact that Yahoo itself asserts it is not using greylisting as a technique to control mail seems to have no effect on the number of people who believe that Yahoo is greylisting.
Deeply held beliefs by many senders aside, Yahoo is not greylisting. Yahoo is using temporary failures (4xx) as a way to defer and control mail coming into their servers and their users.
I think much of the problem is that the definition of greylisting is not well understood by the people using the term. Greylisting generally refers to a process of refusing email with a 4xx response the first time delivery is attempted and accepting the email at the second delivery attempt. There are a number of ways to greylist, per message, per IP or per from address. The defining feature of greylisting is that the receiving MTA keeps track of the messages (IP or addresss) that it has rejected and allows the mail through the second time the mail is sent.
This technique for handling email is a direct response to some spamming software, particularly software that uses infected Windows machines to send email. The spam software will drop any email in response to a 4xx or 5xx response. Well designed software will retry any email receiving a 4xx response. By rejecting anything on the first attempt with a 4xx, the receiving ISPs can trivially block mail from spambots.
Where does this fit in with what Yahoo is doing? Yahoo is not keeping track of the mail it rejects and is not reliably allowing email through on the second attempt. There are a couple reasons why Yahoo is deferring mail.

Read More

Legitimate mail in spamfilters

It can be difficult and frustrating for a sender to understand they whys and wherefores of spam filtering. Clearly the sender is not spamming, so why is their mail getting caught in spam filters?
I have a client that goes through this frustration on rare occasions. They send well crafted, fun, engaging content that their users really want. They have a solid reputation at the ISPs and their inbox stats are always above 98%. Very, very occasionally, though, they will see some filtering difficulties at Postini. It’s sad for all of us because Postini doesn’t tell us enough about what they’re doing to understand what my client is doing to trigger the filters. They get frustrated because they don’t know what’s going wrong; I get frustrated because I can’t really help them, and I’m sure their recipients are frustrated because they don’t get their wanted mail.
Why do a lot of filter vendors not communicate back to listees? Because not all senders are like my clients. Some senders send mail that recipients can take or leave. If the newsletter shows up in their inbox they may read it. If the ad gets in front of their face, they may click through. But, if the mail doesn’t show up, they don’t care. They certainly aren’t going to look for the mail in their bulk folder. Other senders send mail that users really don’t want. It is, flat out, spam.
The thing is, all these senders describe themselves as legitimate email marketers. They harvest addresses, they purchase lists, they send mail to spamtraps, and they still don’t describe themselves as spammers. Some of them have even ended up in court for violating various anti-spam laws and they still claim they’re not spammers.
Senders are competing with spammers for bandwidth and resources at the ISPs, they’re competing for postmaster attention at the ISPs and they’re competing for eyeballs in crowded inboxes.
It’s the sheer volume of spam and the crafty evilness of spammers that drives the constant change and improvement in spamfilters. It’s tough to keep up with the spamfilters because they’re trying to keep up with the spammers. And the spammers are continually looking for new ways to exploit recipients.
It can be a challenge to send relevant, engaging email while dealing with spamfilters and ISPs. But that’s what makes this job so much fun.

Read More