Monday, October 02, 2006

SEO related HTTP Response Codes

Here is the list of HTTP Response codes that I think are important for SEO’s to watch for.

1). 200 OK, this means everything is perfect! Your file was successfully transferred and all is good.

2). 301, if you have intended for your page to redirect to another file then you are in good shape. The 301 header is a redirect message telling the browser/crawler that the page has moved.

3). 302, this means that you have specified that you are temporarily moving your file from one place to another. Also known as the redirect of death, if you must redirect to a new location do NOT use a 302 it can commonly damage your rankings and cause you a lot of head ache. Never ever use this!

I keep hearing that the major search engines have fixed all of the bugs related to 302’s, don’t believe them. Make sure you are protecting yourself.

4). 304, this is the not modified response. If you have a static site and hardly ever update your pages, the web server will respond with a 304 the page has not changed. Your cache date within Google will not change if you see this. If you want to make sure your pages stay fresh put in a date somewhere in your static pages and change them once a day. This will ensure that your pages are fresh.

If you have a Linux hosting environment you can use the “touch command” to update your file. This only changes the last modified date of the file, not the content.

Example:
bash-3.00$ touch index.html

If you want to automate this, you can write a Shell script that can be added to a Cron Job on your server.

5). All 400 and 500 errors are bad news. Make sure you are looking for these in your log files.

If you want to examine your log files for spider errors try this. It will allow you to see problems on your site.

Go to your linux command prompt. Change directories to your log files and experiment with the following command.

“more access-log | grep Googlebot | grep 404” if there is too much information to look at adjust your command to create a file with this search. “more access-log | grep Googlebot | grep 404 > spider-404-output.txt” This will create a file called spider-404-output.txt, and can give you an in site to what the search engines are seeing. You can always replace the 404 with another error code, say for example 500, to see other errors.

Here is a list of all the bad errors to watch out for.

400 Bad Request – Usually a bad request from the client, or if the link to this page was fallowed it may have formed a bad URL.

401 Unauthorized – If you are using password protection, you might see this.

402 Payment Required – This is a custom code, not used very often

403 Forbidden – Rarely used, usually a 404 is used instead.

404 – Not Found, watch for this one, and make sure that all of your pages are there.

405 – Method Not Allowed – Usually invalid header information, this one is not very commonly found.

406 – Not Acceptable – Again this one is very rarely used, but could be a server miss-configuration.

407 – Proxy Authentication Required – This one might be found on an internal company server where the IT department wants to make sure they are not being overloaded. Or that they can track your usage.

408 – Request Timeout – Commonly a server configuration problem, check your memory allotments.

409 – Conflict – Rarely used, no simple answer for this error.

410 – Gone – Page is gone and no forwarding information is available, not used very often.

411 – Length Required – Server miss configuration, very rarely used today.

412 – Precondition Failed – This would come up for custom header requests, very rarely used.

413 – Request Entity Too Large – Server config problem, common with early versions of Apache

414 – Request URI is Too Long – URI prefix is too long and pointing back too-itself, I have never seen this one reported.

415 – Unsupported Media Type – Common for really old web servers, unlikely to ever appear.

416 – Request Range Not Satisfiable – Very rare, usually a config problem. I have only seen this on Netscape servers.

417 – Exception Failed – Usually an extra character that came across the header, sometimes a bad link or cookie. Or just poor config.

500 – Internal Server Error – Almost always a bad config in Apache.

501 – Not Implemented – I rarely see this error, sometimes in Tomcat

502 – Bad Gateway – Commonly a Proxy problem or some strange network config

503 – Service Unavailable – You might be running out of server resources, RAM, CPU etc. Try upping your available server sessions or increase your client limit.

504 – Gateway Timeout – DNS problems, network problems. Not usually a web server problem.

505 – HTTP Version Not Supported – Should be self explanatory but if you see this, could be bad code, server config problem or a bad browser.

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2 Comments:

Blogger Patarsort Business... said...

bonjour,
pouvons-nous faire un échange de liens ?
merci !
Patrick

10:07 AM  
Blogger Nadya said...

This post has been removed by a blog administrator.

12:45 PM  

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Name: Aaron Shear
Location: San Francisco, California, United States

I have been in the search industry since the late 90’s, no not 10-20 years. My career started early in the search Day’s at Inktomi, where I supported large search portals. For example, MSN, AOL, iWon, Hotbot, CNet too name a few. After Inktomi I became a freelance consultant. I consulted for a few of the Top SEO’s around 2002 time frame; obviously the market has changed since then. After consulting I joined a small SEO firm called SEO Inc as the CTO. At SEO Inc. I successfully optimized some of the largest clients including IGN, Sony, VEGAS.com, Beaches and Sandals Resorts to name a few. Even though SEO Inc was a ton of fun, I still wanted the ultimate SEO challenge. I moved on as the global head of SEO for Shopping.com an eBay company. This challenge was an interesting one, how do I optimize a site with 50 million products? Every month I helped the business grow by leaps and bounds. I am now consulting for mostly enterprise e-commerce clients. Yes there is more too me than this profile shows, but you will just have to ask.

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