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Topic: What does "404 Error" mean? |
Brint Hannay
From:
Maryland, USA
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Posted 29 May 2009 7:22 am |
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| What does "404 Error" mean, and when it blocks access to a page what can I do about it? Why is it that when I've landed on a "404 Error" page, it's impossible to get out of it with the back arrow? Repeated back arrows do nothing--the 404 page won't go away. |
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Wiz Feinberg
From:
Mid-Michigan, USA
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Posted 29 May 2009 7:57 am
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A 404 Error means "Page Not Found." When you try to visit a URL that is non-existent, has been removed, has gone missing, has been renamed (but not properly redirected), or is incorrectly spelled, the http server lets you know about the error by announcing 404 - File Not Found.
The back button is grayed out because the server has responded to your request and the page you asked for does not exist as requested. If you were on another working page when you clicked a link that resulted in the 404, the back arrow would work. It is links that open in a new tab or window that don't give you a back function, since there is nothing saved in the browser's memory to return to.
If you get a 404 error when typing a URL you may have misspelled a character. If you get a 404 when clicking on a link, there may be extra characters appended to the link that don't belong there. Check the link to make sure it doesn't end in a comma, colon, semi-colon, period, hyphen, exclamation mark, parenthesis, or bracket. Links in forwarded or replied to emails are notorious for having line breaks inserted that destroy part of a URL.
If you were expecting a link from a friend or supplier and it leads to a 404, please notify them so they can fix the error.
_________________
"Wiz" Feinberg, Moderator SGF Computers Forum
Security Consultant
Twitter: @Wizcrafts
Main web pages: Wiztunes Steel Guitar website | Wiz's Security Blog | My Webmaster Services | Wiz's Security Blog |
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Brint Hannay
From:
Maryland, USA
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Posted 29 May 2009 9:33 am
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Here's an example from a Forum thread.
http://bb.steelguitarforum.com/viewtopic.php?t=158215&start=25
In the fourth post on the page, Mitch Drumm provides a link to "Bill Boyd--New Steel Guitar Rag", in the form that is not a URL. Eddie Cunningham replies, apparently having heard the sound file, so it apparently exists, and can be accessed. But when I click on the link, I get a 404 Error page.
In that instance, the back arrow is indeed greyed out. And I can return to the Forum page by closing the "page not found" tab (I'm using Firefox). But in other instances, e.g. someone sends me, in e-mail, today, a link to the URL of a web page they themselves have read (I'm pretty sure the sender has copied and pasted the URL, rather than typing it), I get the 404 Error page with the back arrow NOT greyed out, but if I hit the back arrow the 404 page flashes off for a fraction of a second, then comes back. I can only get out of it by closing my browser.
The 404 page I'm getting seems to be connected with AVG Anti-Virus, as it says something about disabling the "404 redirect" by going to the AVG Options page.
Last edited by Brint Hannay on 29 May 2009 9:47 am; edited 2 times in total |
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Mitch Drumm
From:
Frostbite Falls, hard by Veronica Lake
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Posted 29 May 2009 9:39 am
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Brint:
In this specific case, the 404 error means nothing more than that I deleted the song in question from the web site on which it was stored. That song was available for only a few days. |
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Brint Hannay
From:
Maryland, USA
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Posted 29 May 2009 9:42 am
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| Thanks, Mitch, that clears THAT up, anyway. |
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Wiz Feinberg
From:
Mid-Michigan, USA
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Posted 29 May 2009 6:22 pm
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In case anybody is curious, here are the meanings of some common Server error codes.
400 - Bad Request - The request contains bad syntax or cannot be fulfilled.
401 - Unauthorized - Authorization Required - you need a user name and password to get access.
403 - Forbidden - you are not getting the resource you requested, no how, no way. This is served to people or bots that have been specifically blocked in .htaccess, or who request a file or folder that has been marked as off-limits to the public. Some Webmasters, like me, will ban visitors/bots who repeatedly try to access forbidden files or folders.
404 - Not Found - already discussed above - File Not Found means it is deleted, renamed, moved, or misspelled. This could be a temporarily missing file, so check back again, or check your link or spelling.
405 - Method Not Allowed - the method you used to access the website is not approved by the webmaster or administrator. Be more friendly to the server and you will be allowed in. I serve up 405's to script kiddie hackers attempting to exploit php scripts I don't even have.
410 - Gone - this is a notice that the file was there but has been permanently deleted, not moved or renamed. Similar to a 404, but with permanence rather than a temporary situation.
500 - Internal Server Error - the Webmaster, or a bad line of code in a script has "FooBarred" the website. This is usually discovered and fixed fairly quickly. Nobody gets in if the 500 error is caused by a bad directive in the .htaccess file on an Apache Server driven website, until the bad code has been fixed.
503 - Service Temporarily Unavailable - Go away and try again later. Too many requests are coming at the same time and the HTTP server can't keep up, so it shuts out all new requests until things settle down. This could be the result of a DDoS attack, or a website that has suddenly become very popular.
_________________
"Wiz" Feinberg, Moderator SGF Computers Forum
Security Consultant
Twitter: @Wizcrafts
Main web pages: Wiztunes Steel Guitar website | Wiz's Security Blog | My Webmaster Services | Wiz's Security Blog |
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Alan Brookes
From:
Brummy living in Southern California
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Posted 29 May 2009 6:54 pm
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...and does "666 Error" mean the Devil has gotten into your computer and it'll be hell to get him out ?  |
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Brint Hannay
From:
Maryland, USA
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Posted 29 May 2009 9:57 pm
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| Wiz, Mitch explained the one example I gave. What should I understand about the other? Actually, there were two links in the same e-mail--one to NPR, the other to The Baltimore Sun newspaper website. Both gave me the same result: infinitely repeating (with active back arrow) 404 Error page. She obviously had read the pages, and no more than a couple of hours later I couldn't. What gives? |
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Wiz Feinberg
From:
Mid-Michigan, USA
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Posted 29 May 2009 11:17 pm
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| Brint Hannay wrote: |
| Wiz, Mitch explained the one example I gave. What should I understand about the other? Actually, there were two links in the same e-mail--one to NPR, the other to The Baltimore Sun newspaper website. Both gave me the same result: infinitely repeating (with active back arrow) 404 Error page. She obviously had read the pages, and no more than a couple of hours later I couldn't. What gives? |
I don't know what happened to those links or pages. As I mentioned before in this thread, sometimes when people forward or reply to an email the word wrap gets changed to a lesser number of characters, causing long words (URLS) to have forced line breaks. If a line break splits a URL in an email it will no longer point to the correct file location and you will get a server 404 response.
Sometimes a period is appended to the end of a URL, when it was meant to just be the end of the sentence. That period will cause a 404 error.
_________________
"Wiz" Feinberg, Moderator SGF Computers Forum
Security Consultant
Twitter: @Wizcrafts
Main web pages: Wiztunes Steel Guitar website | Wiz's Security Blog | My Webmaster Services | Wiz's Security Blog |
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