Flushing DNS cache

We recently had a customer who needed an update to DNS, and it was taking a very, very long time to propagate. While researching how to help fix it, I found these sites that may come in handy.

To see what’s going on with DNS propagation, use this tool: What Is My DNS

And if you ever need to check a particular DNS server’s entries, use this: Query a DNS Server

Plus a very handy page describing how to use nslookup: 10 Most Used nslookup Commands

Redirecting attachment pages in WordPress

Spammers are a crafty bunch, using a variety of techniques to spread their unwanted junk. One way they do this is by submitting comments to the special pages WordPress creates for each image that has been uploaded. Spammers find these pages and submit spam. But there are ways to thwart their misdeeds!

7 Ways to Redirect WordPress Attachment Pages

Lately we’ve been using the Redirect Attachment Pages plugin, if the client does not have it available through an SEO plugin.

Finding large files on Linux

I had a client running out of disk space, and support gave me the command to find all the big stuff. This is to find files larger than 10MB. It prints a list ordered by smallest to largest.

sudo find / -mount -noleaf -type f -size +10000k -print0 | xargs -0 ls -lhSr | perl -ne ‘/(\S+\s+){4}(\S+)\s+(\S+\s+){3}(.*)/ and printf(“%*s %s\n”,7,$2.”:”,$4);’

One thing to note is that this didn’t include mailboxes… they must be stored somewhere else on this particular server. The culprit in this case turned out to be a mailbox that was 15GB (!!). 

Validating fields in Gravity Forms

Despite CAPTCHA, spammers have been submitting spam forms on a few of our client’s websites. The submissions usually have the same first and last name, and often contain a website address in the message. I was able to add a little code to the theme’s functions.php to prevent this type of thing.

add_filter( 'gform_validation_1', 'validate_contact_fields_1' );
function validate_contact_fields_1( $validation_result ) {
    $form = $validation_result['form'];
    // first and last name can't be the same
    if ( rgpost( 'input_1' ) == rgpost( 'input_2' ) ) {
        // set the form validation to false
        $validation_result['is_valid'] = false;
        //finding Field with ID of 1 and marking it as failed validation
        foreach( $form['fields'] as &$field ) {
            //NOTE: replace 1 with the field you would like to validate
            if ( $field->id == '1' ) {
                $field->failed_validation = true;
                $field->validation_message = 'First and Last Name can not be the same.';
    // Message can't contain a URL
    $nourl_pattern = '(http|https)';
    if ( preg_match( $nourl_pattern, rgpost( 'input_4' ) ) ) {

		$validation_result['is_valid'] = false;
        foreach( $form['fields'] as &$field ) {
            if ( $field->id == '4' ) {
                $field->failed_validation = true;
                $field->validation_message = 'Message can not contain website addresses.';
    //Assign modified $form object back to the validation result
    $validation_result['form'] = $form;
    return $validation_result;
}  // end function validate_contact_fields_1

Fixing anchor links that scroll too far down the page

For the second time, I needed to adjust the CSS for a site that is using anchor links. The problem was, the page would scroll down too far because of a fixed menu at the top of the page, and the anchor link area ended up underneath the menu.

The fix is to add this to the site’s CSS:

:target:before {
height:55px; /* fixed header height*/
margin:-55px 0 0; /* negative fixed header height */

Change the height and margin to match the height of the fixed menu. Sometimes the display setting needs a little tweaking, too. Woo!

Dejunking WordPress options

While investigating a slow WordPress installation, I came across this post on how to check if autoloaded options are a factor in the slowdown.

How To Remove Unwanted Autoloaded Data on a WordPress Website

I had no idea that plugins would leave so much junk behind! Here are the two queries to investigate. One to see how big the total options are, and the second to find the worst offenders.

SELECT SUM(LENGTH(option_value)) as autoload_size FROM wp_options WHERE autoload=’yes’;

SELECT LENGTH(option_value),option_name FROM wp_options WHERE autoload=’yes’ ORDER BY length(option_value) DESC LIMIT 15;

For the site I was working on, I set the unnecessary options to autoload=’no’ … just in case it would affect the site.