After startup, ComputerA cannot ping ComputerB.

[Stefan Lasiewski]

Hi everyone,

I have a simple network setup: Two Windows2K boxes, one Linksys
BEFSR41, one network.

My problem in a Nutshell: ComputerA cannot ping ComputerB. ComputerB
_can_ ping ComputerA.

The Linksys assigns IP addresses to the two Win2k boxes via DHCP, and
assigns numbers like 192.168.1.100, .101, etc. No big suprises so far.

Here is what happens when I start the two computers:

- I turn on ComputerA, it boots, is assigned the IP address of
192.168.1.101 and everything seems fine. I go to the command prompt,
and type "ping -t 192.168.1.100" to watch the bootup progress of
ComputerB.

I turn on ComputerB, it boots, and is assigned the IP address of
192.168.1.100.

I go back to watch the progress of the ping command on ComputerA, and
I see that ComputerA can temporarily ping ComputerB. It looks like
this:

C:\Documents and Settings\Stefan Lasiewski>ping -t 192.168.1.100

Pinging 192.168.1.100 with 32 bytes of data:

Request timed out.
Request timed out.
----- Ping repeats with this failure until I see the
----- "Please wait ... Windows is starting up" box.
Reply from 192.168.1.100: bytes=32 time<10ms TTL=128
Reply from 192.168.1.100: bytes=32 time<10ms TTL=128
----- Ping repeats witht his success for approximately 20 times,
----- and then ping is unable to see 192.168.1.100 .
Request timed out.
Request timed out.


Afterwards, ComputerB can ping the IP address of ComputerA, and can
see ComputerA's shares.

However, ComputerA cannot ping the IP address of computerB.

Both computers can access the Internet, see the Linksys at 192.168.1.1
, etc.

This setup has worked for about 6 months. Something changed recently,
and I cannot figure out what the heck happened.

I have even deleted the Connection Profile from Network Properties,
reinstalled drivers, etc.

If I boot ComputerB in safe mode, then ComputerA can ping ComputerB.

If I boot ComputerB into Linux (It is dual Boot), ComputerA can ping
ComputerB just fine. This only happens when both computers are booted
into Windows.

I appreciate any help. This is driving me crazy. Thank you in advance.

-= Stefan

 

[Jim]

Sounds like a classic case of a firewall on "B" (192.168.1.100). Since the
firewall isn't completely erected once the TCP/IP stack is initialized, you
can ping it briefly. But eventually the firewall is erected, then you're
locked out. "B" can always ping "A" though because "A" doesn't have this
same firewall. And since the problem only happens in Windows, again, sure
sign this is a Windows application acting as a firewall (you don't have the
equivalent being loaded in your other OS, so it works fine). I'd verify
that you don't have ICF enabled, or perhaps installed some other firewall
(Norton Internet Security, McAfee, Zone Alarm, etc.).

Jim

 

[Stefan Lasiewski]

Indeed, that was the problem.

I have a VPN on this machine, and the VPN has a firewall component
which runs even when the VPN is not running (I haven't used the VPN in
weeks).

Now, I need to figure out how to configure the VPN's firewall to be
secure but still allow my wife to access on my printer. No
documentation. Woot!

Thanks for your help,

-= Stefan