Internet Network issues

Recently my company LAN has some internet traffic issues.
For no apparent reasons, we will get disconnect from the internet.
Internet Explorer will give the "Page cannot be display" message and
downloads will be cut off etc.
This problem happens intermittently (5-6 times) every day for 3 days.

Whenever this problem happens, I did these:
1) ping to the website (both overseas and local)
2) tracert to the website
3) ping the DNSes (change to both our own DNS (Winnt4) as well as ISP)
4) Check firewall (Gnatbox), SDSL unit (512kb leased line), router(Chase
IOlink)

With these results:
1) website is responding, no drop pings. (pings using both IP address and
host name)
2) all the route hops are responding too
3) DNS are responding too, our local DNS do not have any error logs.
4) All other equipments are behaving normally, even restarted them.

This is strange as ping packets are responding but internet traffic is not.
Anyone can shed some light?

thanks

The only thing ping actually tests is "ping" (ICMP). Ping does not
test TCP or UDP or GRE. Just because ICMP works doesn't mean the TCP &
UDP work.

It is possible to allow ICMP and not TCP/UDP, by the same token
TCP/UDP can be allowed while ICMP is blocked. So ping can test
physical connectivity but does nothing to test Layer4 and above.

You may have a firewall issue where it is flaking out on you, but I
don't know,...there just isn't anything given here to really go on.

--

Phillip Windell [CCNA, MVP, MCP]
WAND-TV (ABC Affiliate)
www.wandtv.com

"David" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Recently my company LAN has some internet traffic issues.
> For no apparent reasons, we will get disconnect from the internet.
> Internet Explorer will give the "Page cannot be display" message and
> downloads will be cut off etc.
> This problem happens intermittently (5-6 times) every day for 3
days.
>
> Whenever this problem happens, I did these:
> 1) ping to the website (both overseas and local)
> 2) tracert to the website
> 3) ping the DNSes (change to both our own DNS (Winnt4) as well as
ISP)
> 4) Check firewall (Gnatbox), SDSL unit (512kb leased line),
router(Chase
> IOlink)
>
> With these results:
> 1) website is responding, no drop pings. (pings using both IP
address and
> host name)
> 2) all the route hops are responding too
> 3) DNS are responding too, our local DNS do not have any error logs.
> 4) All other equipments are behaving normally, even restarted them.
>
> This is strange as ping packets are responding but internet traffic
is not.
> Anyone can shed some light?
>
> thanks
>
>
>

beats me it could be an issue w/ your ISP have you talked
w/ them yet? someone could be playing with the firewall.
you apperently have connictivity. is all of your software
up to date?
>-----Original Message-----
>Recently my company LAN has some internet traffic issues.
>For no apparent reasons, we will get disconnect from the
internet.
>Internet Explorer will give the "Page cannot be display"
message and
>downloads will be cut off etc.
>This problem happens intermittently (5-6 times) every day
for 3 days.
>
>Whenever this problem happens, I did these:
>1) ping to the website (both overseas and local)
>2) tracert to the website
>3) ping the DNSes (change to both our own DNS (Winnt4) as
well as ISP)
>4) Check firewall (Gnatbox), SDSL unit (512kb leased
line), router(Chase
>IOlink)
>
>With these results:
>1) website is responding, no drop pings. (pings using
both IP address and
>host name)
>2) all the route hops are responding too
>3) DNS are responding too, our local DNS do not have any
error logs.
>4) All other equipments are behaving normally, even
restarted them.
>
>This is strange as ping packets are responding but
internet traffic is not.
>Anyone can shed some light?
>
>thanks
>
>
>
>.
>

Hi Phillip,

I am now looking into the firewall as well as verifying with my ISP.
Firewall rules just changed by a colleague some time ago.

Hopefully can resolve it.

thanks

"Phillip Windell" <none> wrote in message
news:(E-Mail Removed)...
> The only thing ping actually tests is "ping" (ICMP). Ping does not
> test TCP or UDP or GRE. Just because ICMP works doesn't mean the TCP &
> UDP work.
>
> It is possible to allow ICMP and not TCP/UDP, by the same token
> TCP/UDP can be allowed while ICMP is blocked. So ping can test
> physical connectivity but does nothing to test Layer4 and above.
>
> You may have a firewall issue where it is flaking out on you, but I
> don't know,...there just isn't anything given here to really go on.
>
> --
>
> Phillip Windell [CCNA, MVP, MCP]
> WAND-TV (ABC Affiliate)
> www.wandtv.com
>
> "David" <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
> > Recently my company LAN has some internet traffic issues.
> > For no apparent reasons, we will get disconnect from the internet.
> > Internet Explorer will give the "Page cannot be display" message and
> > downloads will be cut off etc.
> > This problem happens intermittently (5-6 times) every day for 3
> days.
> >
> > Whenever this problem happens, I did these:
> > 1) ping to the website (both overseas and local)
> > 2) tracert to the website
> > 3) ping the DNSes (change to both our own DNS (Winnt4) as well as
> ISP)
> > 4) Check firewall (Gnatbox), SDSL unit (512kb leased line),
> router(Chase
> > IOlink)
> >
> > With these results:
> > 1) website is responding, no drop pings. (pings using both IP
> address and
> > host name)
> > 2) all the route hops are responding too
> > 3) DNS are responding too, our local DNS do not have any error logs.
> > 4) All other equipments are behaving normally, even restarted them.
> >
> > This is strange as ping packets are responding but internet traffic
> is not.
> > Anyone can shed some light?
> >
> > thanks
> >
> >
> >
>
>