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Department of Civil and Environmental Engineering
Frank Batten College of Engineering and Technology
Old Dominion University
Norfolk, Virginia 23529-0241, USA
Tel) (757) 683-3753
Fax) (757) 683-5354


	
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Dealing with Connection Problems to a Site


  
"Eschew obfuscation"
- Groucho Marx

If you are unable to access the site because your computer doesn't seem to be able to 'find' the site (such as web/ftp program returns 'invalid host' or 'unable to resolve hostname' or some similar errormessage), try one of the following ways to see if the name of the site is known:

  • Telnet works on all systems as long as the system is hooked to the network. Telnet to the site and see if that works, if it does, there's either no ftp server active at the site or there's a configuration error with your ftp client program. Normally, the error message would be something like: 'I/O error on network device' or you do get a connection with the ftp server but it says 'Service not available. Remote service has closed the connection'.

  • Try 'nslookup sitename' or 'host sitename' and see what that gives. If they can't find the site, your nameserver (the computer that looks up the addresses of computers) doesn't know the site 'sitename'. You can try again in a couple of minutes if you think it might be a delay between 'sitename' and your machine. If that doesn't help then either your site has a deficient nameserver (ask your local system administrator to fix it) or the site 'sitename' does not exist.

  • Try is 'ping,' 'traceroute' or 'hopcheck' to see if there is a clear link (or path) to the machine 'sitename'.

  • Easy ways to check if the name 'sitename' can be found outside of your domain (i.e., odu.edu) is by mailing to one of the following addresses:

    service@nic.ddn.mil Use 'host sitename' as the subject of the message. Also other options, send 'help' as the subject.

    dns@grasp.insa-lyon.fr Put 'ip sitename' (no quotes) in the body or 'help' for an info file. Lots of options available.

If a problem appears while accessing the site or when retrieving a file, mail the problems to the system administrator of the site. When you report a problem, please be very explicit, i.e. don't write 'I can't get a file' but explain when it happened, what file it was, what system you are using etc. And word your message politely. It's no use to annoy an system administrator if you want a file from that site. (use your common sense)

If an system administrator address is not obtainable, attempt to use 'ftp@site_name'; replace 'site_name' with the name of the troublesome site. If it's very urgent, try sending a note describing the problem to 'postmaster@site_name' or 'root@site_name' (for Unix system) or 'operator@site_name' (for VAX/VMS machine). The 'postmaster@site_name' should be valid in all cases.


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