Strange TCPIP problem -- cannot reach DNS server

[John Wirt]

I have Comcast Internet service. Lately, the connection has been
intermittent. Some times it works and sometimes it does not. Comcast help
has been, well, little help. Currently, they think that if I get rid of my
Linksys modem and switch to a Comcast modem (for $175 vs $60 for my Linksys
modem), the problem will be solved. I do not think this is the problem

The NIC connected to Comcast is set to automatically retreive the IP address
of the connection and a DNS server address. If I release the current
settings with,

ipconfig /release

and then renew them,

ipconfig /renew

the previous (and valid) Comcast IP address is retrieved and the correct DNS
addresses for that IP address is retireved.

The problem is that I cannot connect to the Internet with Internet Explorer
("server not found") or download email ("cannot access server".

I can ping known IP addresses and get 4 quick replies. If I ping a URL
(e.g., www.yahoo.com), the ping times out. When I ping the Comcast DNS
addresses for my IP addresses 68.87.73.242 and 68.87.71.226), the command
hangs. It does not even time out.

Apparently, the reason I am unable to connect to the Internet is that DNS in
my NIC is not working. Does anyone know what the specific problem is so that
I can fix it?

John Wirt

 

[Herb Martin]

I have Comcast Internet service. Lately, the connection has been
intermittent. Some times it works and sometimes it does not. Comcast help
has been, well, little help. Currently, they think that if I get rid of my
Linksys modem and switch to a Comcast modem (for $175 vs $60 for my
Linksys
modem), the problem will be solved. I do not think this is the problem

Neither do I. And better would likely be to "get rid of Comcast"
and switch to a decent service if that is their attitue OR their price
for what should be a very cheap (under $100) device. ($60
sounds about right.)

In fact, many such services will GIVE you the router-modem
to get you to use the service.

The NIC connected to Comcast is set to automatically retreive the IP
address
of the connection and a DNS server address. If I release the current
settings with,

ipconfig /release

and then renew them,

ipconfig /renew

the previous (and valid) Comcast IP address is retrieved and the correct
DNS
addresses for that IP address is retireved.

The problem is that I cannot connect to the Internet with Internet
Explorer
("server not found") or download email ("cannot access server".

What happens if you perform a DIRECT request with NSLookup?

nslookup www.google.com IP.of.Comcast.DNS

....versus just:

nslookup www.google.com

Without an IP it will use the same DNS server that IE would use.

I can ping known IP addresses and get 4 quick replies. If I ping a URL
(e.g., www.yahoo.com), the ping times out. When I ping the Comcast DNS
addresses for my IP addresses 68.87.73.242 and 68.87.71.226), the command
hangs. It does not even time out.

Well, if ping won't work, then you have a routing problem most
likely.

Try TRACERT when ping fails to see "how far" you get.....

Apparently, the reason I am unable to connect to the Internet is that DNS
in
my NIC is not working. Does anyone know what the specific problem is so
that
I can fix it?

No, it sounds like your IP isn't routing -- likely you aren't
even contacting the DNS server either.

You test and determine such things by trying IP addresses
vs. DNS names. IF IP fails too then you do NOT have a
DNS problem but rather a more fundamental IP issue.

Here are some Google addresses (www.google.com) so
you can test Ping and Tracert by address:

64.233.167.104, 64.233.167.147, 64.233.167.99