I started seeing some folks complain about false CBL listings a few hours ago. I’m now seeing the same folks saying the listings are being removed.
The symptoms look similar to what happened in November (mentioned here), but it appears the CBL team are on top of things and are working to rectify things quickly.
The CBL website is back on line.
It’s possible that your local DNS resolver has old values for it cached. If so, and if you can’t flush your local DNS cache, and you really can’t wait until DNS has been updated then you may be able to put a temporary entry in your hosts file to point to cbl.abuseat.org.
You can get the IP address you need to add by querying the nameserver at ns-2038.awsdns-62.co.uk for cbl.abuseat.org. No, I’m not going to tell you the IP address – if you can’t do a basic DNS query, you shouldn’t be modifying your hosts file and you can just wait a day.
Spamhaus has mostly mitigated the dDOS against the Spamhaus website and mailserver, but now the CBL is under attack. They have been working to get that under protection as well, but it’s taking some time.
Right now there are no public channels for delisting from the CBL. The Spamhaus Blog will be updated as things change, and I’ll try and keep things updated here as well.
UPDATE: Cloudflare talks about the scope of the attack
Just yesterday a group of delivery folks were discussing email verification services over IRC. We were talking about the pros and cons, when we’d suggest using them, when we wouldn’t, which ones we’ve worked with and what our experiences have been. I’ve been contemplating writing up some of my thoughts about verification services but it’s a post I wanted to spend some time on to really address the good parts and the bad parts of verification services.
Today, Spamhaus beat me to the punch and posted a long article on how they view email verification services. (I know that some Spamhaus folks are part of that IRC channel, but I don’t think anyone was around for the discussion we had yesterday.)
It’s well worth a read for anyone who wants some insight into how email verification is viewed by Spamhaus. Their viewpoints are pretty consistent with what I’ve heard from various ISP representatives as well.
In terms of my own thoughts on verification services, I think it’s important to remember that the bulk of the verification services only verify that an address is deliverable. The services do not verify that the address belongs to the person who input it into a form. The services do not verify that an address matches a purchased profile. The services do not verify that the recipient wants email from the senders.
Some of the services claim they remove spamtraps, but their knowledge of spamtraps is limited. Yes, stick around this industry long enough and you’ll identify different spamtraps, and even spamtrap domains. I could probably rattle off a few dozen traps if pressed, but that’s not going to be enough to protect any sender from significant problems.
Some services can be used for real time verification, and that is a place where I think verification can be useful. But I also know there are a number of creative ways to do verification that also check things like permission and data validity.
From an ESP perspective, verification services remove bounces. This means that ESPs have less data to apply to compliance decisions. Bounce rate, particularly for new lists, tells the ESP a lot about the health of the mailing list. Without that, they are mostly relying on complaint data to determine if a customer is following the AUP.
Spamhaus talks about what practices verification services should adopt in order to be above board. They mention actions like clearly identifying their IPs and domains, not switching IPs to avoid blocks and not using dozens or hundreds of IPs. I fully support these recommendations.
Email verification services do provide some benefit to some senders. I can’t help feeling, though, that their main benefit is simply lowering bounce rates and not actually improving the quality of their customers’ signup processes.