Here's a cool tool that a colleague at Valimail created recently, and if you care about protecting against people spoofing your emails through lookalike domains, I think you might find it i…
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Today on DELIVTERMS , the series here on Spam Resource where we help decode email and deliverability terminology, we're digging into something that's absolutely everywher…
Example SMTP Errors When sending email messages to the various AT&T consumer email domains (ameritech.net, att.net, bellsouth.net, currently.com, flash.net, nvbell.net, pacbe…
It’s time to decode another deliverability definition. PSL stands for the Public Suffix List , and it’s one of those things that a certain subset of email geeks (and maybe web de…
Let’s decode another acronym! DNS is a term not limited to email deliverability, but it sure does show up there quite a bit. And it stands for: Domain Name System. DNS is the pho…
Has this one ever happened to you? Your DNS record is there – and then it’s not. Or it’s there when you check certain DNS servers, but not others. Or you hit “reload” on a DNS l…
Here's a new oops that I've observed a few times recently! In case you didn't know already, you can't have two DMARC records for your domain name. (I'm not ta…
If you're one of those weirdos (like me) who tracks what email providers hosts mail for what domains, you'll want to take note of this. In the email industry's ongoin…
When sending to Microsoft OLC (Outlook Consumer - i.e. hotmail.com, outlook.com, msn.com, live.com, etc.) domains, are you seeing this bounce message? Microsoft: 5.4.4 (unable to…
So much going on in the past week in the world of email deliverability. Multiple email platforms (ISPs/MBPs) and sending platforms (ESPs) having problems or unexpected downtime. …
Did you know? For the past fifteen years, I've run a simple little website called Wombatmail that provides a set of DNS lookup tools. My goal was to have a simple set of too…
Are you seeing this bounce message when trying to send mail to Yahoo subscribers? 451 Message temporarily deferred due to unresolvable RFC.5321 from domain; see https://postmaste…
A friend warned me of a scenario that could have the potential to freak people out, if misunderstood. It looks like this: This person is using Spamhaus to filter inbound mail. Th…
Julia Evans aka b0rk is somebody smart that I follow on Twitter. She created this super cool tool that I've linked to on social media before, called Mess with DNS , providi…
Speaking of Spamhaus, this just popped up in my RSS feed reader. It looks like Spamhaus is going to take a harder stance against users who query their lists via open or public D…
I've long had a little banner at the bottom of my xnnd.com DNS tools site that says "since 2008" but it looks like I'm going to have to change that. Looking th…
Cloudflare just launched their own public DNS service . To try it, simply configure your computer to use the DNS servers 1.1.1.1 and 1.0.0.1 . Then your computer's DNS looku…
Steve Atkins of Word to the Wise just released a cool new tool: SPF Minimizer . Over on the Word to the Wise blog, he explains how it works and provides an extremely insightful …
Steven Champeon says , "If your PTR contains or ends with IN-ADDR.ARPA, you're Doing It Wrong. Go read a book. That is all."
