How to handle Internet error messages

"The sad thing about Unix is that no matter how many times you hit yourself over the head with it, you never quite manage to lose consciousness." If you've ever stumbled over cryptic browser messages such as 400: Bad request or 404: Not found you may appreciate some of the hostility that is directed towards Unix, the operating system upon which most of the World Wide Web is built.

Mostly, this lack of user friendliness doesn't matter, as it remains hidden from the average Internet user. But if you come face to face with any of those not-so-rare Internet error messages which somehow make you feel as if you're to blame, you're going to need some Unix-to-human translation to understand what's gone wrong.

400: Bad request The address you typed is somehow incorrect. The URL may not exist or you may not have authority to access the document on the server.

What to do: Check that you typed the URL correctly. Remember that Internet addresses are case sensitive, so www.pagopago.com/Holidays is not the same as www.pagopago.com/holidays. If you're not used to typing URLs, it's very easy to leave out the correct punctuation or to substitute a slosh (\) for a slash (/). Computers are very finicky about this stuff.

If you're trying an address you found elsewhere -- perhaps in a magazine or on a Web site -- it's possible that the original author got it wrong. You might want to check the capitalisation or try just the first part of the address. For instance, if you can't get to www.pagopago.com/Holidays, try www.pagopago.com by itself, and then see if you can manually navigate to the Holidays page.

401: Unauthorised. You're treading on restricted ground. The page you've tried to access is only available to people authorised by the host or those with the correct password. Sites can also restrict access to those people who are connecting from a particular domain: for instance, you might only be able to access a site if you connect via a .edu or .gov domain or via a particular country domain.

What to do: If you know you should have access to the site, check the spelling of your password, including the case.

403: Forbidden This is very like 401. The page you're trying to view is password protected or restricted in some other way.

What to do: If you have the password for the site, check the spelling. If you still can't get in, you may need to e-mail the site's Webmaster.

404: Not found The particular page you're looking for can't be found on the server. It may be that the page no longer exists (remember, the Web is a very volatile place and no page lives forever) or that it's been moved to another location or renamed.

What to do: Once again, check the spelling of the URL. You can also try going up one or more levels and seeing if you can locate the page that way. For instance, if you're looking for www.microsoft.com/ie/IE40/security.asp and can't seem to find it, try www.microsoft.com/ie/IE40 and, if that doesn't help, try www.microsoft.com/ie and finally www.microsoft.com. Once you manage to load a page, you can then try navigating your way to the page or using the site's search facility, if it has one, to locate the page you want.

500: Internal Error There's something wrong at the Web site itself. As their server is not functioning correctly, it's unable to provide you with the requested Web page. What to do: Contact the site's Webmaster or administrator, or try again later in the hope that they have noticed the problem and fixed it themselves.

502: Service temporarily overloaded This one's fairly self evident: so many people are accessing the server that it can't handle the load.

What to do: Try again later. If it's a very high-traffic site, try accessing it at a time when most people are likely to be asleep. If it's a US-based site, this is pretty easy to accomplish.

503: Service unavailable This is a "temporarily out of order" sign, and it's sometimes reported as Gateway timeout. It means either the server that hosts the site is currently not working or is unavailable, your ISP's server is down, or your own system or company Internet gateway (if you're on a LAN) is not working.

What to do: Wait a minute and try again. If you get the message for a lengthy period or with every attempt to connect to any site, check that your PC and LAN connections are functioning, and then check with your ISP or the remote site. This may entail a phone call to their tech support line.

Bad file request You've requested a page that contains a form with a feature your browser can't support.

What to do: Let the Webmaster know the form is unusable.

Connection refused by host Like the Forbidden and Unauthorised messages, this one usually means you've tried to access a password-protected site or one that's restricted to users from particular domains.

What to do: If you have the password, check that you typed it correctly and try again. If it still won't work, contact the Webmaster.

Failed DNS lookup You've typed a URL that can't be converted into a valid Internet address.

What to do: Check that you typed the URL correctly. If you did, wait a few seconds and try again.

File contains no data You've connected to a server that doesn't have any Web documents on it.

What to do: Try the URL once more. If you still get the same message, try again later: it may be that you've stumbled onto the site just as it's being updated.

Helper application not found or Viewer not found Most browsers require additional programs to 'view' files such as sound clips, video, 3D VRML pages, Zip (compressed) files, spreadsheets and so on.

What to do: The latest versions of the major browsers usually offer to install the required 'viewer' or 'helper' program automatically. If you want to view the file, click OK to install the program and follow the prompts. If your browser doesn't prompt you for automatic installation, you'll usually find the error message provides information about the type of file that can't be viewed. Look for a reference to graphic, VRML, audio and so on. Most sites will provide a link to another site where you can download a viewer. Alternatively, check out PC User's Net Sites/Plug-ins listing (at www.pcuser.com.au ) or try out Netscape's extensive list of plug-ins at http://home.netscape.com/comprod/products/navigator/version_2.0/plugins/index.html   and its guide to configuring helper applications at http://home.netscape.com/assist/helper_apps/index.html

Host unavailable The site's server is currently down.

What to do: Try again a few times. If you still can't get in, the site may be down for maintenance. Try again later.

Host unknown It could be that the site's server is down (as with the previous message) or that your modem lost the connection.

What to do: First try re-accessing the site by hitting the Reload button. Make sure you've typed the URL correctly and that you're still online.

Network connection was refused by the server This usually means you've come across an overworked server that can't handle any more users. This is the message you get if the server hasn't been set up to display the more informative "Service temporarily overloaded" message.

What to do: Try again. If you still don't get on, be patient and try again later.

NNTP server error This is a Usenet newsgroup error message. You'll come across it when you're trying to join a newsgroup but can't get access.

What to do: First, make sure you typed the newsgroup address correctly. If you did, try again later. If you still can't get on, it may be that your ISP doesn't provide access to that particular newsgroup -- you'll need to contact your ISP to find out and, perhaps, complain about its absence.

Permission denied This is an FTP message which you'll see if you try to upload a file to an FTP site and the site administrator doesn't want you to. You may also see it if you try to download a file using the wrong syntax or simply when the site is to busy to handle an upload.

What to do: Check that you're using the correct syntax. If so, try again later. If you still can't upload the file, contact the site's administrator.

Too many connections -- try again later You're trying to access a site that's already overwhelmed with visitors.

What to do: Try again a few times and, if you still can't get in, try again later.

Too many users This is the FTP equivalent of the 'Too many connections' message. FTP sites allow a certain number of anonymous connections at any one time. If you try to log on when that limit is reached, you'll receive this message.

What to do: Keep on trying. Remember, some of the really big download sites, such as Netscape and Tucows, have mirror sites elsewhere which make the same files available. If you are locked out of the main site by heavy traffic, see if you can find a mirror site to use.

Unable to locate host This is similar to the Host unknown message. It means the site's server is unavailable at the moment, or that you've lost the modem connection.

What to do: Check the spelling of the URL and click Reload to see if you can get through. If not, make sure you're online. You may need to wait and try later.

Unable to locate the server The particular server where the site is located cannot be found -- either it no longer exists or you've got the URL wrong.

What to do: Check your spelling.

You can't log on as an anonymous user This is a message from an FTP site. Either the site doesn't provide anonymous access, or it's reached its limit for anonymous users.

What to do: Try again later. If you're using your browser to access the FTP site, make sure you've configured it correctly: most FTP sites require an ID of anonymous and your e-mail address as the password.