TCP/IP computer can ping world, world can't ping computer

[Alex Acuna]

Hi

I'm having a really strange situation going on with one of my Win2000
computers.

As the subject line states, it can ping and access the world (within
and outside of the LAN), however, no other computer can ping it (ie.
ping 192.168.2.3).

This machine is able to browse the web and ping everywhere, but no
other computer can ping it, which means that my XPPro laptop, which
doesn't have the netbui protocol installed, can't access the shares on
the w2k computer.

This machine is connected to a belkin 4 port router (which acts as the
DHCP server). If I set the machine to use a static IP address, it
can't browse the web at all.

I ran winsockfix.exe on it, which kinda resolved the internet access
problem (as long as the computer uses a dynamic IP address).

Also, I have no firewall running.

I already tried replacing the network card (as instructed in other,
similar, threads).

Next stop seems to be a full reinstall of windows 2000 unless someone
comes up with another clever idea.

Thanks in advance!!!!!

Alex

Here's a dump from ipconfig /a:
Windows 2000 IP Configuration



Host Name . . . . . . . . . . . . : ws04
Primary DNS Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Broadcast

IP Routing Enabled. . . . . . . . : Yes

WINS Proxy Enabled. . . . . . . . : No


Ethernet adapter Local Area Connection 3:



Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : 3Com EtherLink XL 10/100 PCI For
Complete PC Management NIC (3C905C-TX)
Physical Address. . . . . . . . . : 00-04-75-C9-4C-CB

DHCP Enabled. . . . . . . . . . . : Yes

Autoconfiguration Enabled . . . . : Yes

IP Address. . . . . . . . . . . . : 192.168.2.3

Subnet Mask . . . . . . . . . . . : 255.255.255.0

Default Gateway . . . . . . . . . : 192.168.2.1

DHCP Server . . . . . . . . . . . : 192.168.2.1

DNS Servers . . . . . . . . . . . : 192.168.2.1
Lease Obtained. . . . . . . . . . : Wednesday, December 17, 2003
5:26:49 PM

Lease Expires . . . . . . . . . . : Monday, January 18, 2038 10:14:07
PM

 

[David Robbins]

Hi

I'm having a really strange situation going on with one of my Win2000
computers.

As the subject line states, it can ping and access the world (within
and outside of the LAN), however, no other computer can ping it (ie.
ping 192.168.2.3).

this is your basic problem. that ip address is not an internet routable
address. the 192.168.*.* block is reserved for internal lan's only and will
not be visible from the internet... indeed that address can be reused
anywhere in the world on many, many lans so there would be no way for any
internet router to know where to send a ping. you say you are behind a
router, that router must be doing nat and supplying your lan machines with
those addresses. this means that the internal lan machines are hidden from
the outside world, which is usually a good thing since it protects them like
a completely closed firewall. the router itself will have the ip address
that is visible from outside.

if you need to access your machine from the internet side of your router you
will need to see how that router configures access for servers to get
through the nat it does. each router has its own way of doing that, read
the documentation and if that doesn't help ask the support address from that
company.

 

[Alex Acuna]

Hi David,

Perhaps I wasn't clear enough. I need to ping that w2k computer from
within the same lan. I know that that address is supplied by the
router's dhcp server.

This computer can ping other computers in the LAN but no computer in
the LAN can ping it.

This computer can also ping any computer on the internet. I'm not
interested in computers outside of the realm of this lan pinging
anything within the lan.

Thanks for trying!

Alex

 

[David Robbins]

well, if it can ping and get its replies then the hardware is most likely
ok. that would leave the possibilities of a firewall blocking icmp requests
coming into the machine. or a rather unlikely case of a corrupt tcp/ip
stack that is ignoring just that protocol. can you ping 127.0.0.1? that
would probably rule out the corrupt stack. otherwise make sure there isn't
a firewall running in the machine or router that would block icmp.

 

[Alex Acuna]

Hi David,

I'm able to ping 127.0.0.1 from the problem PC, so according to your
message, my tcp/ip stack is ok.

As far as I know, there's no firewall in the machine. The router has
one though, and it's enabled, however, this doesn't prevent me from
pinging other pc's in the LAN, so it shouldn't affect this one either.

I did notice something strange as I was going through the
configuration of the router (web based). Before, in order to access
the problem PC via pc-anywhere I've had to enter the following info in
the Virtual Server page of the router's config:

Priv. IP: Priv. Port: Type: Public Port:
192.168.2.8 5631 TCP 5631
192.168.2.8 5632 UDP 5632

(192.168.2.8 was the IP address of this PC at the time I set it up for
pc-anywhere - obtained from router's dhcp server.)

Now, PC-Anywhere is working even though this PC's IP address is
192.168.2.3, which is different from what I have in the Virtual Server
page.

Don't know if this may shed some light on the problem, but mentioned
it just in case.

Thanks for your help!

Alex