Opera [
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Microsoft Internet Explorer [
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Apache Server is classic HTTP server application. Even that is not the only one, their status codes and messages becomes standard of HTTP. Getting an error message can be frustraded, but it is not always impossible to overcome them. In this tutorial, we will look closely how to handle situations like this.
Please see "Surfer's Basic Knowledge" tutorial, for miscellanous details, e.g. about URL.
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Standard error messages are pure functional, without no estetic. These messages can be rewritten by a special named sites. A 404.htm is a good example. As you can see at table below, 404 error is arised when user request a file which not exist. There is no difference, if it is an archive, clip, image or web-page (html file). By default, server should return pure text web-page, which will be vissible on any hardware - including military telegraphs and the last generation mobile phones. However, when webmaster design its own page and inform server about its existence at special configuration file, server will response with this page.
Some of these error sites are laconic and spartian, some are beautiful and useful for webmaster, because they collect information about your tooken steps and can generate an anonymous e-mail. They will not call your mail-client, so you will not send your address. They are also a smart 404 error pages, which offers you search or redirect you to main entry page. Somewhere in the middle are error-pages full of colour adverts - they are usually a trap, of course and it is not a rare situation that this site is the only one site on free-web-space besides of main index!
Tip: Place cursor over picture or link, or - if message at status bar does not change - right-click on page and choose "Download all by Net Transport", and see what the links looks like. Adverts links usually starts with http://click4cash ..., or http://clickz.webmasterprogram ..., and there is always a parameter (on the end) like ?siteid= ..., or simple ?id= ... . Not all adverts are automatically bad, but if there are 8 banners on one single page, what conclussion you can make?
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Opera [
Full picture ] |
Microsoft Internet Explorer [
Full picture ] |
Picture 1: "404 Not Found" standard error page:
Opera and Microsoft Internet Explorer
Please note, the search option at Microsoft Internet Explorer. By the way, this
Search is possible being done automaticly.
Microsoft Internet Explorer ver. 5.x and later shows its own 404 page (picture 1 right) instead of stardard message (picture 1 left) - i.e. in situation when domain has no 404 site, or that this site is not correctly configured. What is interesting? Presence of Search button. Try to guess what happend when you click on it. It is also a way how to build-up a database for search engines and grows up - in size, speed and accurancy.
A specially 404 sites is a big bussiness - probably the second after e-mail-boxes and spammers. Open some web-search engine for example and try to search for "404 traffic" exact phrase. Just read a short notices and descriptions which you get in return and you should get an picture. Or, look for picture 2, at least.
More or less 20% of link are broken on internet, according to Net Ratings agency. We must not walk far for example - click for this link. It is from my own and because of free-web-hoisting with limited traffic, portal owner just forward you to its main page. There are a lot of useful links, but a few (expensive) banners and - I have read, but I do not believe it - even personal-preffered-like adverts also.
Picture 2: "404 traffic", first attempt to search
this phrase, 2003-07-01
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Full picture ]
Tip: The most beautiful 404 sites have their own gallery at http://www.404lounge.net/index.php3. Some of them are really piece of art - hope, not only as sumplemental for missing content.
User should see only codes 400 (sometimes refered as DNS look-up fails) and, in case of server-hardware-crush, 500. Codes 300 are usually handled automatically without any necessary action from user, but all browsers can dissable this redirection, because this has been widely misused. Codes 100 are not exist at HTTP1.0 and are used exclussivelly by HTTP1.1 protocols - e.g. crypted streams attempt.
Following table contains full pack of HTTP 1.1 server standard response with short description. You are a client, of course.
Code |
Standard
response |
Description |
Informational |
||
| 100 | Continue |
Go ahead, we will understand our-self. |
| 101 | Switching
Protocols |
This is happend when you e.g. attempt to streaming media |
Succesful
client request |
||
200 |
Ok | Accepted, processed and here is the result. What is next? |
201 |
Created | Your personal copy of file based on your request's parameters |
202 |
Accepted | Accepted, but cannot be fullfiled |
203 |
Non-Authorative Information | Not from original, but borrowed from third-party |
204 |
No Content | Accepted, processed, but without result |
205 |
Reset Content | Displayed information time is expired, allready |
206 |
Partial Content | Cannot be processed fully. However on multi-stream transport it can be a correct answer for partial file request. |
Client
request redirected |
||
300 |
Multiple Choices | A few identical copies found - any of them is valid |
301 |
Moved Permanently | Usually is redirection automatic. There is always an info page with link to new location |
302 |
(Found) Moved Temporarily | dtto |
303 |
See Other | Not available now, but here is a simillar information |
304 |
Not Modified | Is information expired or still valid? |
305 |
Use Proxy | You must be accessed through proxy, otherwise sorry. |
| 306 | Reserved | Not use anymore, but reserved |
| 307 | Temporary Redirect | For some reason (e.g. over-traffic) is request redirected to mirror |
| 400 | Bad Request | Bad syntax, mostly a type-error at URL (missing dot in domain, wrong domain
name, page has extension "htm"
and you write "html",
and simmilar). In most cases you can solve this situation, if you delete a file name from address, so you leave only protocol, server and path and your address will finish with "/". Browser shall find an index page for itself. But be sure first that server name is correct! See also 404. |
| Authorization Required | Wrong password to restricted area - generally server
did not receive correct encryption ID. As part of URL passwords
are always CaSe sensitive! Other possibility is that server denny access from certain domain types: e.g. law at some countries prohibits visual "arts" because of religion, so server-owner can block requests from web-portals in these locations. See also 403. |
|
402 |
Payment Required | Currently not used, but it is quite possible that it will be, because of "free preview and increase quality after fee" files are used more and more frequently. |
| Forbidden | Access is forbidden - simillar to 401
but there is a difference. You are blocked because of server limitation
reached. The common reason is that you are using stolen passwords and server notes that hundred of other IP addresses use them too, already. Or password has been stolen you - you should contact an administrator in this case. Sometimes you need to sign-in even to public sites or groups. Other alternative is that you downloaded too much, already. Use some other proxy. |
|
| Not Found | File is not found, because does not exist physically on server any more.
Link you just written is broken. Or you made some mistyped error at file
name or its path (server name and protocol is correct for sure). You can solve this situation in the same way as 400 error. |
|
| 405 | Method Not Allowed | Very rare error, because you as user hardly can perform modifying operation. |
| 406 | Not Acceptable | Encoding is not acceptable. Unicode UTF-8 should be used - it is the safest - you can set it at any browser |
| 407 | Proxy Authentication Required | You should dissable any application
- mostly firewalls and advert - removers - which hide or scramble
your IP. Also you should enable cookies. Server
shall not comunicate with anonymous. This technique of authorization - simillar to 401 - is used by almost any of leased-content-providers. You are at some restricted area and you are forwarding to completelly other server and URL which own content itself (that area buy content use). See also 401. |
| 408 | Request Timed Out | You did not send a request within server time-limit, so you are going
to be disconnected to not occupy connection capacity. You should log-in again, if necessary. |
| 409 | Conflicting Request | Touches only different HTTP versions. Most browser has possibilities to dissable using HTTP1.1 - it can help. |
| 410 | Gone | Streaming media mainly. Request has been fullfiled, sent to you, and forgotten
- no information about new URL is and shall be available. You should ask again and be more quicker this time. |
| 411 | Content Length Required | Also streaming media - you must declare how long clip
should be. If you delete any of file parameters (part after "?"), you should paste them back. |
| 412 | Precondition Failed | You are training to get other file or conditions than web-master indeed via handly rewritting parameters. Server is not going to tolerate this. |
| 413 | Request Entity Too Long | You are asking for too much quantity of data - it is
not a rare error when using download manager, in fact. Your connection will
be restricted, or even denied for some time, just as prevention of over-traffic. Pause a downloads and try later (after a few minutes - it is usually far enough). |
| 414 | Request URI Too Long | Address you written is too long - limit is usually 400 chars. Extremally
long URLs are used by e.g. Yahoo, or most of directories portals, which
refer themselfs. You should try to copy only address itself and paste it. It can work. |
| 415 | Unsupported Media Type | If you are asking a stream-media from pure web-server, e.g. |
| 416 | Requested Range Not Satisfiable | It can be an answer for rewritting communication ports. |
| 417 | Expectation Failed | Server can not serve you under conditions you wish to. |
Server
errors |
||
| 500 | Internal Server Error | Something unexpected - mostly hardware crush |
| 501 | Not Implemented | Server can not fullfil request because it do not know how to process e.g. protocol. |
| 502 | Bad Gateway | This server you can not use as proxy - other server do not want to communicate with it. |
| 503 | Service Unavailable | Service is unavailable mostly only to you - the cookies acceptation is necessary in most cases. Other possibility is that there is an maintenance in progress on it, and there is no other mirror to use. |
| 504 | Gateway Time-Out | In fact, server is very slow for using as proxy. |
| 505 | HTTP Version Not Supported | This trick has been proposed to stop Peer2Peer networks. Lawyers have had the vission to duty update the application to the version which shall never be released. |
Full description of errors and programming details of their handling can be found at Apache server documentation, of course. The newest version is accessible on-line from "Apache HTTP Server Project" at this link to main entry. Error themself and illegal moves which should arrise them are standardized by W3C Organization at full specification about HTTP 1.1 titled RFC 2616. Extraction about errors is e.g. here.
You can encounter also for a few errors which are displayed in critical error's dialogs. Here they are collected.
No
DNS Entry |
DNS is that 4 bytes - it is an interpreted address used by machines during communication (not with human). You probably misstyped URL at server name, but it is quite possible, that your primary server is just temporarily over-traffic |
Bad
File Request / Too Many Users |
This is a problem of HTML source-code for site, mainly. Other possibility is that your browser does not support a form (such as embeded media or GIF format) you are trying to access. E-mail web-master details, he will be glad for them. |
File
Contains No Data |
You have made no mistake, but administrator just uploading site upgrade. Try later. |
Viewer
not found |
You have no viewer installed to see content (e.g. you attempt for RealVideo without RealPlayer installed). Most of browser give you a possibility to save the file to local disk, anyway - you can do that and matter about player later. |
Host
Unavailable |
Try later, but through Shift + "Reload" button! |
NNTP
Server Error |
Usenet newsgroups and a few possible problems: as usually, server can be down, you can make a mistake in address, or you can wrongly set yor preferences for this news-group |
Permission
Dennied |
You are not allowed to upload files into FTP server. Try to retype URL first, if not help, try later, and if still nothing change, write to administrator and ask him for explanation. |
Unable
to Locate Host |
Host can be down, or you made some mistake at address. But the common reason is, that your Internet connection has been lost. It can be also an over-traffic problem, try to access later or at early morning. |
Unable
to Locate Server |
Only misstyping, nothing else. |
You
cannot Log as an Anonymous User |
FTP site is accessible only for registered members, or, you have to provide at least your e-mail address, if you are an guest and site clearly shows that guests are welcomed there. If you are a registered user, log-into server and type passwords handly instead of using them as a part of URL. |
Microsoft Internet Explorer use by default HTTP version 1.1. You can dissable this at Micorosoft Internet Explorer :: Tools > Properties :: (last tab) Advanced > HTTP 1.1 settings. See pic. 3. You can encounter - very-very-rare - that Net Transport does not finish HTTP download at 100% but continue a while futher. This can happend at HTTP 0.98 and if the file is correct, just ignore this.
On the same tab at list's top, you can dissable URL auto-looking from address bar and UTF-8 encoding for URL - see pic. 3 also.
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 |
 |
HTTP ver. 1.1 handle's settings |
Auto-look-up for URL from Address bar dissabled |
URL will be always send at Unicode UTF-8 encoding |
Picture 3: Microsoft
Internet Explorer ::
Tools > Properties tabbed dialog box.
Click on pictures to see them on their full - size. Or [
here for left ] one, [
here for middle ] one and [
here for right ] one.
Countless time I have been called to set-up cookies - task, which suddenly turns into restoring all general security setup. Cookies can be set at Micorosoft Internet Explorer :: Tools > Properties :: (third tab) Privacy! Do not enter, or change settings at second tab titled as Security! It is not necessary to go in there for changing cookies' security level! You should delete cookies after you finish with your internet session - definitelly, if you have not a NTFS hard disk, or you finish at internet-café. Interesting, that Microsoft Internet Explorer does not offer deleting cookies automatically - you must do it handly at first tab General - but, has set for default deleting files from Temporary Internet Directory ... I wrote a special tutorial about Cookies, where you can find more details. Here just two facts: cookies are harmless, cookies can be used as a part of authorization (it makes tracking from where you really come from much more easier).
 |
 |
Cookies are to being set at this tab ... |
and not at this! |
Picture 4: Microsoft
Internet Explorer ::
Tools > Properties tabbed dialog box - cookies settings.
Ignore a misstyped error at word "cookies" in left
window.
Click on pictures to see them on their full - size. Or [
here for left ] one and [
here for right ] one.
 |
 |
Temporary Internet Files can be deleted automaticly
... |
but cookies, can not. ~comment
skipped~ |
Picture 5: Microsoft
Internet Explorer ::
Tools > Properties tabbed dialog box.
Click on pictures to see them on their full - size. Or [
here for left ] one and [
here for right ] one.
When I start with Security options - specially , when you are a home-user connected through 56k modem - always look at what dialog are you clicking on and what you allows to install. No matter if ActiveX element, plug-in or dialer-program.
There has been one special program - you can find it even now but with different design - which offers a free access to one of biggest and oldest adult-oriented portal. It is a dialer, but very smart. When you install it for the first time, it silence volume, force its window to be centered and on top, disconnect you and connect you again through international calls through Kiribati (islands at Pacific). So, if you has a modem-card, you will not heard and see that you are disconnecting. Application itself use a few techniques, which confuse third-party-content servers and convince them, that you are really accessing from members area. Well, it works. And you can be sure, that membership is cheaper than even a one-hour-phone-bill for this connection!
When you hear that modem beeps and should not or see that leds/icon blinks, disconnect cable immediatelly - throw it away from socket at modem, if necessary.
Opera 7 has no settings for HTTP version use - it handle switching protocols automatically. Also, it has no auto-looking for broken links. You can search for information you choose from Address bar using appropriate prefix - e.g. when you enter "g Opera skin free download" it will look over internet for that sentence using Google. Or you can search a special Search bar and look for information using a few search-engines at once. But you have to do it handly - no auto-search and search from 404 window is implemented.
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 |
URL will be always send at Unicode UTF-8 encoding |
Cookies settings |
Picture 6: Opera
7 :: File >
Preferencies list dialog box.
Click on pictures to see them on their full - size. Or [
here for left ] one and [
here for right ] one.
Encoding URL to international Unicode UTF-8 encoding can be forced by option wit same name at Preferencies dialog (Opera 7 :: File > Preferences, or Alt + P short-cut) at Network tab - see pic. 6 on left.
Temporary Internet Files directory is called "Disk cache" by Opera. Its settings are at Preferences dialog at History and Cache tab.
Cookies can be set at Preferences dialog at Privacy tab. Options are by my opinion much more understable that those at Microsoft Internet Explorer. Quickly you can dissable all cookies throgh File > Quick Preferences :: Enable cookies, or by pressing F12 key. You can also set deleting new cookies automatically. I wrote a special tutorial about Cookies, where you can find more details.
Most of tricks - such as ActiveX elements or browser plug-ins - are not allowed at Opera. However, you can still download and install a dialer!
Net Transport - as you rather should expect from download manager - handle automaticly and re-connect to server if connection fails as result of time-outs or over-traffic. This is main purpose, why it have been developed. Just for curiosity, click on any Thread when you funishing with download. You can see, how Net Transport communicate with server - e.g. asking it for a partial content.
Shortly said, endless counting of connection is result of 403 errors mainly, failed downloads are result of 400 or 401. When 404 error is encountered you usually download at least appropriatte http-error-page. Net Transport can return about 100 different errors. It hits the point exactly, so you will for sure know what goes wrong.
Nothing more could be said without repeating information that are provided at original documentation (FAQ) or at "Hunting for ..." manuals suite at this domain. If you skip an client request errors section - or displayed as pages, or as dialogs - please, look there also.
As I mentioned, authorization duo username:password can be a part of URI. Address written to address bar has in this case following structure: protocol://username:password@host/path/filename. It looks, e.g. like http://asd123xcvbnm:987a654b321c0@www.restrict2entry.com/memberssectiononly/.
Microsoft disabled this form of authorization for Microsoft Internet Explorer at the latest service pack. Both for Microsoft Windows XP and for Microsoft Internet Explorer only. When you use this form, you will get - as usually, very detailed description: “Invalid Syntax Error”.
You have to write only URL without authorization, and appropriate password should be enter when prompted.
A few individuals hidden behind pseudonyms said, that Microsoft wants to disable password piracy, which grown rapidly with wireless connection to internet. It is very easy to monitoring internet traffic at free-of-charge frequencies, because only a few ISP providers use an encryption. I personally doubt, that this is true reason. It is a fact, that this reference can be easily misappropriate – and it is heavily misused at free-access sites! There are a few examples mentioned at original Microsoft Knowledge Database Article Q834489.
Please download this registry update file and install it. If you do not understand, please read the whole article here - or better download it here.
2004-07-25
A part about cookies is extended.
2004-03-12
A section about "Invalid Syntax Error" added. A multi-stream request
of 206 response added.
You can translate or link this tutorial under conditions written at this domain's "Legal Stuff" page and followed. If any doubts, please contact me.
Copyrights, trademarks and credits are collected here.
Marián Stach
Prešov, Slovakia Central Europe
2003-07-06
