Your hard work on search engine optimization (SEO) won’t matter if your server isn’t set up to properly deliver pages and codes to search engines and your customers. You have to keep your server happy and healthy. Use this table to diagnose server problems, sort out redirects, and ensure that everything is working as it should, and you’ll minimize SEO problems.
| Code | Description | Definition | What It Means |
|---|---|---|---|
| 200 | OK | The web page appears as expected. | You want to see this status. Your server and web page have the welcome mat out for search engine spiders (and users, too). |
| 301 | Moved Permanently | The web page has been redirected permanently to another web-page URL. | When a search engine spider sees this status code, it moves easily to the appropriate new page. A 301 Redirect status doesn’t cause a problem for search engine optimization. |
| 302 | Found (Moved Temporarily) | The web page has been moved temporarily to a different URL. | This status should raise a red flag if you find it on your web server. Even though people claim legitimate uses for a 302 Redirect code, this code can cause serious problems for your optimization efforts. Spammers frequently use 302 Redirects maliciously, so if you don’t want a search engine mistaking your site for a spam site, avoid them. |
| 400 | Bad Request | The server couldn’t understand the request because of bad syntax. | A typo in the URL could cause this status. Whatever the cause, you don’t want to block a search engine spider from reaching your content pages, so investigate what’s causing this status code on your site. |
| 401 | Unauthorized | The request requires user authentication. | Usually, this status means that you need to log in before you can view the page content. Not a good error for spiders to hit. |
| 403 | Forbidden | The server understood the request but refuses to fulfill it. | If you find this status code on your website, find out why. If you want to block the spiders from entering, have a good reason. |
| 404 | Not Found | The web page isn’t available. | You see this error code as the Page Cannot Be Displayed page that appears when a web site is down or nonexistent. You definitely don’t want a spider following a link to your web site only to be greeted by a 404 error! That’s like visiting a house and finding the lights off and the doors locked. If your server check shows that you have a 404 error for one of your landing pages, fix it ASAP. |
| 500 and up | Miscellaneous server errors | The 500–505 status codes indicate that something’s wrong with your server. Check them out. |