Let’s start with some background information, the site I was working on was a typical wordpress blog running with wp-super-cache and hosted on a slice. I usually develop on my local server with git. I then push the site to my slice.

The trouble came when I decided to revert my code back to a previous instance, and after reviewing my site, I pushed the updates to my slice and turned on wp-super-cache. But after a few hours I noticed my site was continually going offline. Even though it never affected any of the other sites I hosted on that server.

The problem was that git doesn’t remember file permissions and I forgot to tell git to ignore the cache folder. So when I reverted back to a different version it also reverted the cache folder, its contents, and proceeded to change the permissions to what I assume was the default permissions when I first initiated the repository. So not being able to write to the cache folder made wp-super-cache crash the apache process and eventually all the apache processes took all the memory. 

So when using git don’t forget to reset your permissions, when reverting back to an earlier instance of code.

What the heck is an SPF? 

SPF stands for Sender Policy Framework. It allows domain owners to specify which mail servers they use to send mail from their domain. The policy is specified by adding a txt record containing the SPF policy to your domains nameservers. So for SPF to work the receiving mail server needs to be setup to check the sender’s domains policy.

Just because your domain doesn’t have an SPF policy doesn’t mean your email will automatically be labeled as spam, But it can help you get out of the spam folder. An emails header without a SPF policy would look like this: 

Received-SPF: neutral (google.com: 210.19.84.47 is neither permitted nor denied by best guess record for domain of www-data@gnix.us) client-ip=210.19.84.47;

Authentication-Results: mx.google.com; spf=neutral (google.com: 210.19.84.47 is neither permitted nor denied by best guess record for domain of greg[at]gnix.us) smtp.mail=greg[@]gnix.us

Once you add the policy to your nameservers, your headers will look like this: 

Received-SPF: pass (google.com: domain of greg[at]gnix.us designates 210.19.84.47 as permitted sender) client-ip= 210.19.84.47; Authentication-Results: mx.google.com; spf=pass (google.com: domain of greg[at]gnix.us designates 210.19.84.47 as permitted sender) smtp.mail=greg[at]gnix.us

Of course there are a lot of other factors that spam filters use to eliminate spam, but adding an SPF policy is an easy way to add trust between email senders and spam filters.

On SPF’s website, they have a wizard to generate your TXT record. Just input your domain and answer a few questions about which mail servers will be used to send emails from your domain.

SPF isn’t the only protocol that tries to validate the sender of an email. And out of the three big webmail companies (Google, Yahoo, Microsoft) only Google checks for SPF records. Here’s a summary on what the others use.

Microsoft

Sender ID - Is confusingly similar to SPF. they both validate email sender addresses and both use dns records to publish their policies. I won’t get into the differences, but they are different.

Yahoo

Domain Keys Identified Mail (DKIM) - Signs the email with a key, and then the recieving mail server verifies key from a record in the sender’s domain nameservers.

SPF - They don’t check for SPF records, but they do have a SPF policy in their dns records.

Google

SPF, DKIM

If your serious about your email getting through spam filters, you should look into DKIM. Unfortunately DKIM requires a lot more effort to get working, but is probably the most supported.

After a year and half of no website, I finally got my stuff together and built this website. But since this is a brand new site, I’m sure that there will be a few bugs to squash. So feel free to point them out, along with any egregious grammar or spelling mistakes. (I make a lot of them.) 

As far as content goes, and as long as I can stay on topic, 90% of my posts will be about web design. A more detailed list of topics are as follows:

• (x)html
• css
• javascript
• php
• mysql
• server settings
• photoshop
• illustrator