Helping Tips For Web

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There are several things you can try to find a missing link. The most common web error message is 404 Not Found returned when the URL is misspelled or the page just no longer exists. The first 4 indicates a client error, the 0 indicates a syntax error, and the final "4" indicates that the specific problem is that the page could not be found.
You can get a site address by hand, voice, or on paper, but copying and pasting from an electronic document is best since it guarantees that it's spelled correctly -- select the address with your mouse, copy it with <ctrl>-c, and then paste it into the site location field of your browser and press return.

When a page turns up missing, you can try to find it with the following troubleshooting steps:

Net Connection. If the error message says that the site can't be found or reached, check to see if you can reach other sites. Check an up-to-the minute news site you haven't visited yet in this session, so that you can be sure it wasn't just loaded from your cache. If you can reach other sites, then your net connection is fine.

If you can't reach any other site, then your net connection is down. Check all your cables, and if necessary reboot and reconnect.

Character Case. Domain names are usually not case sensitive, but URL path descriptions sometime are. Make sure that the page address has the same mix of upper and lower case as specified in the URL where you originally found it.
Site Can't Be Found. If the error message says that the whole site can't be found, then either the site address is misspelled, the original address was wrong, the site doesn't exist, the site hasn't yet been registered with the net domain name servers, or the site has been closed down.
Port Number. If a site URL includes a port number after the domain name, then different ports might have different sites associated with them. Try dropping the port number, or changing it to 80 or 8080, and see if the same or some related site is found.
Reference Check. Check to see if the address ever did exist by searching for the url on a search engine, and if it isn't found (i.e. no search engine picked it up, and no other page ever linked to it), then you may have the name misspelled or the original reference was wrong.

If the page can't be found but you are sure it did exist, then either the page has been moved somewhere else on the site, moved to another site, or closed down. You can try the following techniques to try and retrieve the data:

Site Search. If the page moved somewhere else on the site, you can sometimes try visiting the square one up from the missing page to see if it has been moved close by.
Web Search. You can search on the page name alone from the URL, which might find the page if it is stored on any mirror sites. However, if the page name is common, like "index.html", then too many results will be returned unless you add some unique identifiers to the search.
Unique Reference. If you know of any unique reference on the page that would not be on any other page, such as a unique title, name, or quotation, you can try searching the web as a phrase to see if anyone else has posted the same material.
Related Information. If all of the above steps fail, then you are left with the option of related information. You can search on keywords you think would be on the page you were looking for, which will generally return pages with similar types of information, and may also provide the information you were looking for.
Archives. You can also sometimes find the last known copy of a missing page in a web archive.

There are several possible causes of connection anomalies. The ping program is very useful for diagnosing connection problems. Common connection anomalies and their solutions are described below:

Lock up. If just your browser is locked up, and other programs still work, then quit and restart your browser.
Net Connection. If none of your usual sites can be located, then your Internet connection is likely down. Check your network connection application. You can restart the connection, and, if that doesn't work, reboot your computer, and try again.
Reload Images. If graphics don't show up, then you can reload the page. If they still don't show up, they probably have been moved and are no longer accessible.
Reload. If there is anything wrong with a page's formatting, try reloading it. Pressing "shift+reload" or "shift+refresh" will sometimes help get a guaranteed new page in all its elements from scratch.

You can diagnose if the site is slow, your connection is slow, or your computer is slow. When your browser is loading a page, the logo at the top of the window flashes to indicate the download is in progress, and statistics describing how the transfer is progressing are displayed on the bottom window border.

A page of text takes on average about a 1,000 characters or bytes. A graphic is on average about 10,000 characters, or 10 KB, and can be up to 100 KB or more. Therefore, pictures take an order of magnitude more space than text, and take longer to download.

For comparison purposes, the number of seconds it takes to download data of various sizes with Internet connections of various speeds is shown in the table below.

Seconds	56 kbps modem	128 kbps ISDN	1.544 Mbps T1	5 Mbps ADSL
1000 B text	0.143	0.0625	0.00518	0.0016
10 KB text or picture	1.43	0.625	0.0518	0.016
100 KB picture	14.3	6.25	0.518	0.16
1 MB video file	142	62.5	5.18	1.6
10 MB application	1428	625	51.8	16

The ping program is useful for diagnosing slow connections. If you find that your page loading is taking a lot longer than it should, consider the following options:

Site slow. If it is just one site that is slow, then there is nothing you can do about it, because the site itself is the cause.
Connection slow. If all sites are slow, and it happens more at certain times of the day, then your Internet Service Provider or the Internet itself are slowing down under higher loads. If the delays are excessive on all sites then the cause is likely your Internet Service Provider, because even under the heaviest loads the Internet backbone continues to provide good performance.
Computer slow. If all sites are slow all the time, even for the speed of your Internet connection, then you need some expert assistance to check and make sure that you have the proper modem configuration, init strings, hardware hand-shaking setup, and other options. Check with your Internet Service Provider and find out what sort of service you should expect. If you are hearing a lot of disk activity during the times that the net is slow, you likely need more RAM memory, which is usually the best way to speed up a computer.

There are a range of common error messages you might receive when visiting a web site. The most frequent web error message is 404 Not Found, returned when the URL is misspelled or the page no longer exists. The most common web error messages and their causes are summarized in the table below. Additional error codes are described in sections 10.4 and 10.5 of RFC 2616.

Error : 400 Bad Request
Cause : The site was found, but the page could not be found. Check the spelling of the URL carefully, including the upper and lower case of the letters. If you still can't find the page, see Finding A Missing Link, and The Virtual City Model.

Error : 401 Unauthorized
Cause :Page exists but is only accessible to specified users (not you). Possibly the site or page has been temporarily taken off-line for maintenance or other activity.

Error : 403 Forbidden Page
Cause :Same as "401 Unauthorized" above.

Error : 404 File Not Found
Cause :Same as "400 Bad Request" above. See the summary at the beginning of this section.

Error : 503 Service Unavailable
Cause :The site is busy, or service has been temporarily suspended. Try again later.

Error : Bad file
Cause :Either your browser doesn't support a feature in the accessed page, or there is an HTML error in the page. Try upgrading your browser to the latest release, or seeing if anyone else can access the page.

Error : Connection refused
Cause :Either the site is serving the maximum number of users, or is temporarily closed to public access. Try again later.

Error : Connection reset by peer
Cause :For some reason the remote side terminated the connection. Try again. If this repeats on one site, there is something wrong with the site. If it repeats on more than one site, you probably have a bad line connection.

Error : Document contains no data
Cause :The page was found, but is empty. It may be being updated. Try again later.

Error : Fatal Error. System call 'fopen' failed: No such file or directory.
Cause :Page has moved, or the URL is wrong.

Error : Failed DNS lookup
Cause :The site cannot be found. Check your spelling. If your spelling is correct, the site has been removed (temporarily or permanently) from the Internet.

Error : File Contains No Data
Cause :Same as "Document Contains No Data" above.

Error : Forbidden - Your client is not allowed to access the requested object
Cause :Same as "401 Unauthorized" above.

Error : Helper application not found
Cause :You tried to access a file for which your browser needs a special helper application. Check the file type referenced in the message, and add the appropriate helper application.

Error : Host unavailable
Cause :The site exists, but is not presently accessible. If you can't access any other site either, then your ISP is down. Otherwise, the site has been taken off the Internet, possibly only temporarily for maintenance. Try again later.

Error : Network connection was refused by the server
Cause :The site is probably just too busy, or down for maintenance. Try again later.

Error : Server does not have a DNS entry
Cause :Same as "Failed DNS lookup" above.

Error : Too Many Connections - Try Again Later
Cause :The site is serving the maximum number of users. Every few minutes try pressing Reload or Refresh until you gain access.

Error : Unable to locate host
Cause :Same as "Host unavailable" above.

Error : You can't log on as an anonymous user
Cause :Usually caused when trying to access an FTP site. The site may already have the maximum number of anonymous users logged in, in which case you should try later. If you still can't get in, it may be that the site does not allow anonymous logins, in which case you will have to use an FTP program to log in with a valid user name.