Your entire work life is in your work mail client. All the people you communicate with – co-workers, friends, family, vendors, customers, colleagues. Every email you send. Every email you receive. Any files you attach or receive. If someone can compromise your mail client, they can see all that. They can save copies of all your emails, data-mine them and use them for whatever purpose they...
I often pull emails into a database to analyze them, but sometimes I want something simpler. Emails are typically stored in one of two ways: mbox format, where an entire mailbox is stored in a single file, and maildir format, where a mailbox is a directory with one file in it for each email. My desktop mail application is Mail.app on OS X, and it stores messages in a maildir-ish format, so...
I’ve had a couple folks come to me recently for help troubleshooting SPF failures. The error messages said the SPF record was invalid, but by all checks it was valid. Eventually, we tracked the issue down to how many include files were in the SPF record. The SPF specification specifically limits the number of lookups that can happen during a SPF check. SPF implementations MUST limit the...
ICANN have signed agreements for four new top level domains, all internationalized domains from the 2o12 applications for new TLDs. They are شبكة (“network” or maybe “web” in arabic), 游戏 (“game” in chinese), онлайн and сайт (“online” and “website” in russian). It’ll take a while for the registries to ramp up their infrastructure...
A number of sources are reporting this morning that there was a problem with some domains in the .com zone yesterday. These problems caused the DNS records of these domains to become corrupted. The records are now fixed. Some of the domains, however, had long TTLs. If a recursive resolver pulled the corrupted records, it could take up to 2 days for the new records to naturally age out. Folks can...
Some email blacklists focus solely on allowing their users to block mail from problematic sources. Others aim to reduce the amount of bad mail sent and prefer senders clean up their practices, rather than just blocking them wholesale. The Spamhaus SBL is one of the second type, using listings both to block mail permanently from irredeemable spammers and as short term encouragement for a sender to...
I’ve been preaching “DKIM is great! DomainKeys is obsolete, get rid of it!” for several years now. I thought I’d take a look at my mailbox and see who was using authentication. I’ve divided this into “Ham” and “Spam”. Spam is, well, all the spam I’ve received over the past couple of years. Ham is the non-spam mail in my inbox, whether...
When you look up a host name, a mailserver or anything else there are three types of reply you can get. The way they’re described varies from tool to tool, but they’re most commonly referred to using the messages dig returns – NXDOMAIN, NOERROR and SERVFAIL. NXDOMAIN is the simplest – it means that there’s no DNS record that matches your query (or any other query for...
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...
Over the weekend I noticed a new CSS framework aimed at email rather than web development, “Antwort“. This isn’t the first or only framework for email content, but this one looks simple and robust, and it allows for content that doesn’t just adapt for different sized displays but looks good on all of them. The idea behind it is to divide your content into columns, magazine...
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