Re: Ask EU: web hosts again

On 06/06/2010 15:04, the Omrud wrote:
On 06/06/2010 13:21, J. P. Gilliver (John) wrote:

The DNS - domain name server/service - is the machinery that turns
gloucestershire-arts-and-crafts.webs.com into 216.52.115.50; most ISPs
keep a list, which is kept up-to-date by talking to other DNSs, and so
on. If the entry (for gloucestershire-arts-and-crafts.webs.com) in a
DNS's table points to something that isn't responding, users can't see
it until the table gets corrected (they can see the site if they type in
216.52.115.50 instead of gloucestershire-arts-and-crafts.webs.com, but
that's not a lot of help to you).

Actually, no they don't: perhaps otherrats who understand these things
better than I do might be able to explain, as it might be germane. I got
the 216.52.115.50 address by pinging
gloucestershire-arts-and-crafts.webs.com (either using Turnpike's ping
function or opening a command prompt and just typing

ping gloucestershire-arts-and-crafts.webs.com

into it); both ping methods give no response, whereas pinging
www.bbc.co.uk tells me that that is 212.58.246.161 and that does respond
to pings.

(They're called pings by analogy with the sonar sound and submarines.
Some sites don't respond to pings, but do to web page requests, so the
lack of response to pings doesn't necessarily mean anything's wrong.)

The relevant rfc's state that they must respond to pings, but many
services disable ping at the firewall, to avoid certain types of attack.
The rules were written in a simpler time when everybody on the Net was a
techie.

In my last job, I had a nice little ping application from tucows or somewhere. Having used it one day, not long after the head of our IT section came up and told me that it was the sort of thing crackers used to break into networks and things. Ergo don't do it again...


--
John Wright

Use your imagination Marvin!

Life's bad enough as it is - why invent any more of it.
.

Relevant Pages

  • Re: Batch file for Ping?
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    (microsoft.public.windows.server.scripting)
  • Re: Batch file for Ping?
    ... the ping can take awhile to timeout when you try ... with the -a option (to resolve the host name), ... Const OpenAsDefault = -2 ... ' Check for response. ...
    (microsoft.public.windows.server.scripting)
  • Re: Cant access broadband
    ... isn't working very well, ping it and look at the responses, if it varies ... their response by getting me to ping a URL rather than an IP? ... ISP loses out. ... my cable modem. ...
    (microsoft.public.windowsxp.network_web)
  • Re: OT Question for Loretta
    ... I think it is better to have written Ping Loretta ... Yup "pinging" was, and still is, used to mean listening for a response to ... The Sonar sent a pinging sound and the equipment operator listened for the ...
    (alt.support.diabetes)
  • RE: ICMP (Ping)
    ... If they are going to attack ... randomly against ranges, they run ping sweeps randomly against ranges, ... almost) running a port scan those that reply. ... >> response. ...
    (Security-Basics)