One of the WordPress websites hosted on our dedicated server produces all the time a wp-cron.php 404 error messages like:
xxx.xxx.xxx.xxx - - [15/Apr/2010:06:32:12 -0600] "POST /wp-cron.php?doing_wp_cron HTTP/1.0
I did not know until recently, whatwp-cron.php does, so I checked in google and red a bit. Many of the places, I've red are aa bit unclear and doesn't give good exlanation on what exactly wp-cron.php does. I wrote this post in hope it will shed some more light on wp-config.php and how this major 404 issue is solved..
what is wp-cron.php doing?
- wp-cron.php is acting like a cron scheduler for WordPress.
- wp-cron.php is a wp file that controls routine actions for particular WordPress install.
- Updates the data in SQL database on every, request, every day or every hour etc. – (depending on how it's set up.).
- wp-cron.php executes automatically by default after EVERY PAGE LOAD!
- Checks all pending comments for spam with Akismet (if akismet or anti-spam plugin alike is installed)
- Sends all scheduled emails (e.g. sent a commentor email when someone comments on his comment functionality, sent newsletter subscribed persons emails etc.)
- Post online scheduled articles for a day and time of particular day
Suppose you're writting a new post and you want to take advantage of WordPress functionality to schedule a post to appear Online at specific time:
The Publish Immediately, field execution is being issued on the scheduled time thanks to the wp-cron.php periodic invocation.
Another example for wp-cron.php operation is in handling flushing of WP old HTML Caches generated by some wordpress caching plugin like W3 Total Cache
wp-cron.php takes care for dozens of other stuff silently in the background. That's why many wordpress plugins are depending heavily on wp-cron.php proper periodic execution. Therefore if something is wrong with wp-config.php, this makes wordpress based blog or website partially working or not working at all.
Our company wp-cron.php errors case
In our case the:
18.104.22.168 – – [15/Apr/2010:06:32:12 -0600] "POST /wp-cron.php?doing_wp_cron HTTP/1.0" 404
is occuring in Apache access.log (after each unique vistor request to wordpress!.), this is cause wp-cron.php is invoked on each new site visitor site request.
This puts a "vain load" on the Apache Server, attempting constatly to invoke the script … always returning not found 404 err.
As a consequence, the WP website experiences "weird" problems all the time. An illustration of a problem caused by the impoper wp-cron.php execution is when we are adding new plugins to WP.
Lets say a new wordpress extension is download, installed and enabled in order to add new useful functioanlity to the site.
Most of the time this new plugin would be malfunctioning if for example it is prepared to add some kind of new html form or change something on some or all the wordpress HTML generated pages.
This troubles are result of wp-config.php's inability to update settings in wp SQL database, after each new user request to our site.
So the newly added plugin website functionality is not showing up at all, until WP cache directory is manually deleted with rm -rf /var/www/blog/wp-content/cache/…
I don't know how thi whole wp-config.php mess occured, however my guess is whoever installed this wordpress has messed something in the install procedure.
Anyways, as I researched thoroughfully, I red many people complaining of having experienced same wp-config.php 404 errs. As I red, most of the people troubles were caused by their shared hosting prohibiting the wp-cron.php execution.
It appears many shared hostings providers choose, to disable the wordpress default wp-cron.php execution. The reason is probably the script puts heavy load on shared hosting servers and makes troubles with server overloads.
Anyhow, since our company server is adedicated server I can tell for sure in our case wordpress had no restrictions for how and when wp-cron.php is invoked.
I've seen also some posts online claiming, the wp-cron.php issues are caused of improper localhost records in /etc/hosts, after a thorough examination I did not found any hosts problems:
hipo@debian:~$ grep -i 127.0.0.1 /etc/hosts
127.0.0.1 localhost.localdomain localhost
You see from below paste, our server, /etc/hosts has perfectly correct 127.0.0.1 records.
Changing default way wp-cron.php is executed
As I've learned it is generally a good idea for WordPress based websites which contain tens of thousands of visitors, to alter the default way wp-cron.php is handled. Doing so will achieve some efficiency and improve server hardware utilization.
Invoking the script, after each visitor request can put a heavy "useless" burden on the server CPU. In most wordpress based websites, the script did not need to make frequent changes in the DB, as new comments in posts did not happen often. In most wordpress installs out there, big changes in the wordpress are not common.
Therefore, a good frequency to exec wp-cron.php, for wordpress blogs getting only a couple of user comments per hour is, half an hour cron routine.
To disable automatic invocation of wp-cron.php, after each visitor request open /var/www/blog/wp-config.php and nearby the line 30 or 40, put:
An important note to make here is that it makes sense the position in wp-config.php, where define('DISABLE_WP_CRON', true); is placed. If for instance you put it at the end of file or near the end of the file, this setting will not take affect.
With that said be sure to put the variable define, somewhere along the file initial defines or it will not work.
Next, with Apache non-root privileged user lets say www-data, httpd, www depending on the Linux distribution or BSD Unix type add a php CLI line to invoke wp-cron.php every half an hour:
linux:~# crontab -u www-data -e
0,30 * * * * cd /var/www/blog; /usr/bin/php /var/www/blog/wp-cron.php 2>&1 >/dev/null
To assure, the php CLI (Command Language Interface) interpreter is capable of properly interpreting the wp-cron.php, check wp-cron.php for syntax errors with cmd:
linux:~# php -l /var/www/blog/wp-cron.php
No syntax errors detected in /var/www/blog/wp-cron.php
That's all, 404 wp-cron.php error messages will not appear anymore in access.log! 🙂
Just for those who can find the root of the /wp-cron.php?doing_wp_cron HTTP/1.0" 404 and fix the issue in some other way (I'll be glad to know how?), there is also another external way to invoke wp-cron.php with a request directly to the webserver with short cron invocation via wget or lynx text browser.
– Here is how to call wp-cron.php every half an hour with lynxPut inside any non-privileged user, something like:
01,30 * * * * /usr/bin/lynx -dump "http://www.your-domain-url.com/wp-cron.php?doing_wp_cron" 2>&1 >/dev/null
– Call wp-cron.php every 30 mins with wget:
01,30 * * * * /usr/bin/wget -q "http://www.your-domain-url.com/wp-cron.php?doing_wp_cron"
Invoke the wp-cron.php less frequently, saves the server from processing the wp-cron.php thousands of useless times.
Altering the way wp-cron.php works should be seen immediately as the reduced server load should drop a bit.
Consider you might need to play with the script exec frequency until you get, best fit cron timing. For my company case there are only up to 3 new article posted a week, hence too high frequence of wp-cron.php invocations is useless.
With blog where new posts occur once a day a script schedule frequency of 6 up to 12 hours should be ok.
Remove URL from comments in WordPress Blogs and Websites to mitigate comment spam URLs in pagesFriday, February 20th, 2015
If you're running a WordPress blog or Website where you have enabled comments for a page and your article or page is well indexing in Google (receives a lot of visit / reads ) daily, your site posts (comments) section is surely to quickly fill in with a lot of "Thank you" and non-sense Spam comments containing an ugly link to an external SPAM or Phishing website.
Such URL links with non-sense message is a favourite way for SPAMmers to raise their website incoming (other website) "InLinks" and through that increase current Search Engine position.
We all know a lot of comments SPAM is generally handled well by Akismet but unfortunately still many of such spam comments fail to be identified as Spam because spam Bots (text-generator algorithms) becomes more and more sophisticated with time, also you can never stop paid a real-persons Marketers to spam you with a smart crafted messages to increase their site's SEO ).
In all those cases Akismet WP (Anti-Spam) plugin – which btw is among the first "must have" WP extensions to install on a new blog / website will be not enough ..
To fight with worsening SEO because of spam URLs and to keep your site's SEO better (having a lot of links pointing to reported spam sites will reduce your overall SEO Index Rate) many WordPress based bloggers, choose to not use default WordPress Comments capabilities – e.g. use exnternal commenting systems such as Disqus – (Web Community of Communities), IntenseDebate, LiveFyre, Vicomi …
However as Disqus and other 3rd party commenting systems are proprietary software (you don't have access to comments data as comments are kept on proprietary platform and shown from there), I don't personally recommend (or use) those ones, yes Disqus, Google+, Facebook and other comment external sources can have a positive impact on your SEO but that's temporary event and on the long run I think it is more advantageous to have comments with yourself.
A small note for people using Disqos and Facebook as comment platforms – (just imagine if Disqos or Facebook bankrupts in future, where your comments will be? 🙂 )
So assuming that you're a novice blogger and I succeeded convincing you to stick to standard (embedded) WordPress Comment System once your site becomes famous you will start getting severe amount of comment spam. There is plenty of articles already written on how to remove URL comment form spam in WordPress but many of the guides online are old or obsolete so in this article I will do a short evaluation on few things I tried to remove comment spam and how I finally managed to disable URL link spam to appear on site.
1. Hide Comment Author Link (Hide-wp-comment-author-link)
This plugin is the best one I found and I started using it since yesterday, I warmly recommend this plugin because its very easy, Download, Unzip, Activate and there you're anything typed in URL field will no longer appear in Posts (note that the URL field will stay so if you want to keep track on person's input URL you can get still see it in Wp-Admin). I'm using default WordPress WRC (Kubrick), but I guess in most newer wordpress plugins is supposed to work. If you test it on another theme please drop a comment to inform whether works for you. Hide Comment Author Link works on current latest Wordpress 4.1 websites.
A similar plugin to hide-wp-author-link that works and you can use is Hide-n-Disable-comment-url-field, I tested this one but for some reason I couldn't make it work.
Whatever I type in Website field in above form, this is wiped out of comment once submitted 🙂
2. Disable hide Comment URL (disable-hide-comment-url)
I've seen reports disable-hide-comment-url works on WordPress 3.9.1, but it didn't worked for me, also the plugin is old and seems no longer maintaned (its last update was 3.5 years ago), if it works for you please please drop in comment your WP version, on WP 4.1 it is not working.
3. WordPress Anti-Spam plugin
WordPress Anti-Spam plugin is a very useful addition plugin to install next to Akismet. The plugin is great if you don't want to remove commenter URL to show in the post but want to cut a lot of the annoying Spam Robots crawling ur site.
Anti-spam plugin blocks spam in comments automatically, invisibly for users and for admins.
Plugin is easy to use: just install it and it just works.
Anti bot works fine on WP 4.1
4. Stop Spam Comments
Stop Spam Comments is:
Stop Spam Comments works fine on WP 4.1.
I've mentioned few of the plugins which can help you solve the problem, but as there are a lot of anti-spam URL plugins available for WP its up to you to test and see what fits you best. If you know or use some other method to protect yourself from Comment Url Spam to share it please.
Import thing to note is it usually a bad idea to mix up different anti-spam plugins so don't enable both Stop Spam Comments and WordPress Anti Spam plugin.
5. Comment Form Remove Url field Manually
This (Liberian) South) African blog describes a way how to remove URL field URL manually
In short to Remove Url Comment Field manually either edit function.php (if you have Shell SSH access) or if not do it via Wp-Admin web interface:
Paste at the end of file following PHP code:
Now to make changes effect, Restart Apache / Nginx Webserver and clean any cache if you're using a plugin like W3 Total Cache plugin etc.
Other good posts describing some manual and embedded WordPress ways to reduce / stop comment spam is here and here, however as it comes to my blog, none of the described manual (code hack) ways I found worked on WordPress v. 4.1.
Thus I personally stuck to using Hide and Disable Comment URL plugin to get rid of comment website URL.
Tags: article, bloggers, btw, data, interface, lot, page, php, platform, problem, running, Search Engine, SEO, spam, Spam Robots, Stop Spam Comments, theme, URLs, use, website, Wordpress Comments, wordpress plugins, wp
Posted in Curious Facts, Various, Web and CMS, Wordpress | 2 Comments »