Win XP Internet connection stopped working

[paulroskilly]

Suddenly internet access has stopped working. I can ping external hosts

ok, both by ip address and domain name, but IE / outlook just doesnt
connect anymore.

Its as if the TCP/IP ports are blocked but I dont know how to find out
whats blocking them.


Ive tried running msconfig and disabling all startup items and
different services but that doesnt help, ran a virus scan which
reported no infected files.


Going mad, thanks for any help.


Paul

 

[Chuck]

Suddenly internet access has stopped working. I can ping external hosts

ok, both by ip address and domain name, but IE / outlook just doesnt
connect anymore.

Its as if the TCP/IP ports are blocked but I dont know how to find out
whats blocking them.


Ive tried running msconfig and disabling all startup items and
different services but that doesnt help, ran a virus scan which
reported no infected files.


Going mad, thanks for any help.


Paul

Paul,

Frequently, when you can ping a host, but not access the web pages on that same
host (you are testing the same host by ping and by browser, right?), you have an
MTU problem. The MTU issue can hit anybody at any time, and it will almost
certainly not hit any 2 people the same.
<http://nitecruzr.blogspot.com/2005/06/internet-connectivity-problems-caused.html>
http://nitecruzr.blogspot.com/2005/06/internet-connectivity-problems-caused.html

 

[paulroskilly]

Thanks Chuck, Ive downloaded some software called DR TCP that lets you
change MTU settings on network adapters, although ive yet to try it
yet.

I wonder if this is the problem though, the computer browsed the
internet fine for a year or so, could a MTU setting change itself and
go too big? I read on one of youre likes that XP sp1 fixed a problem
with MTUs being too big for the PPOE protocol (or something).

Anyway i'll see...

 

[Chuck]

Thanks Chuck, Ive downloaded some software called DR TCP that lets you
change MTU settings on network adapters, although ive yet to try it
yet.

I wonder if this is the problem though, the computer browsed the
internet fine for a year or so, could a MTU setting change itself and
go too big? I read on one of youre likes that XP sp1 fixed a problem
with MTUs being too big for the PPOE protocol (or something).

Anyway i'll see...

Paul,

The MTU problem involves several factors coming together. Any of those factors,
coming or going, can make the problem appear or disappear, for some or all
websites.

XP SP1 was just one of the variants of the problem.

Dr TCP is the tool to use, and careful experimentation is the only method to use
Dr TCP. And you'll only know that the MTU was (or wasn't) the problem when you
fix the problem.

 

[samarjit]

Suddenly internet access has stopped working. I can ping external hosts

ok, both by ip address and domain name, but IE / outlook just doesnt
connect anymore.

Its as if the TCP/IP ports are blocked but I dont know how to find out
whats blocking them.


Ive tried running msconfig and disabling all startup items and
different services but that doesnt help, ran a virus scan which
reported no infected files.


Going mad, thanks for any help.


Paul

 

[paulroskilly]

I have ran Dr TCP on the machine, it showed no setting for the MTU on
the network adapter, so I put in 576 the same as my computer but after
a reboot the machine still has the same problems.

IE / email doesnt work, although I can ping google.com ok from a dos
console, it resolves to an ip address and responds to the ping ok.

I notice that the windows firewall / ICS sharing service isn;t running
which I read can cause problems (you should disable the windows
firewall but not stop the service was the advice), but if i try and
start the service it says it can't.

In control panel -> Security Center it says firewall is running and it
is a norton firewall, but there isn't an option to stop it, I cant see
any service / programs installed to do with norton so dont know how to
stop it, (in case this is interfering with the built in microsoft
firewall service).

I guess id might aswell re-install win xp as a last resort, maybe
uninstalling and reinstalling some windows components would clear it
out?

Thanks for any advice.

Paul