Semi OT for this group, but I'll ask anyway.
I use Mozilla Firefox. Half the time lately, I get unresolved
web sites for links that I click on. If I keep clicking the same
link, I eventually get it.
Can this be virus related? I've downloaded the latest from
Avast and it found 2 viruses, which I've since deleted.
***************** REPLY SEPARATER *****************
It could have something to do with a virus, but not likely.
It could have something to do with Firefox, but not likely.
It more than likely has something to do with your operating system or
the DNS servers that you are using. The first thing to do is check
your DNS settings. If you are using a dynamic IP setting that is DHCP
served, that server should be providing you with the DNS addresses.
Fixed IP and DNS addresses are better, but either way you can check
those settings at the command prompt <ipconfig /all>. You should have
2 DNS servers listed, sometimes called Primary and Secondary. Listing
any more than 2 is overkill, and will only cause DNS timeouts to
become excessively long as it tries each one.
The best way to check availability of a web site is to use the ping
command. In older operating systems (9.x/NT), the browser had it's
own cache, which meant that it could not be trusted as a test. The
newer operating systems (XP/2000) have a system DNS cache, so you
must ensure that the cache is empty in order to conduct a proper
test. The cache speeds things up and takes the load off the DNS
servers, but it can cause problems on sites that are
dynamically/geographically allocated through such services as Akamai
Technologies. These include Yahoo, Spamcop, and even at times
Microsoft. To flush the cache, use another command line commmand
<ipconfig /flushdns>. Now you are ready to execute a ping:
---------------------------------------------------------
C:\>ping
www.bellsouth.net
Pinging filter.bellsouth.net [216.77.188.40] with 32 bytes of data:
Reply from 216.77.188.40: bytes=32 time=74ms TTL=240
Reply from 216.77.188.40: bytes=32 time=67ms TTL=240
Reply from 216.77.188.40: bytes=32 time=67ms TTL=240
Reply from 216.77.188.40: bytes=32 time=68ms TTL=240
Ping statistics for 216.77.188.40:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 67ms, Maximum = 74ms, Average = 69ms
--------------------------------------------------------
This tests 2 functions. It tests that the name can be resolved, and
it tests that the site actually responds. Be aware that some sites
such as Microsoft and CCN do not respond to pings, and also that
sometimes ISPs have to block pings when thay are under a DoS attack.
J.A. Coutts
