A sees B, but B doesn't see A

[Carlos G]

I have two Win2K machines (A and B) and an XP machine (C) on a home network
(via a Linksys router)

I'm able to ping machine A from machine B
I'm NOT able to ping machine B from machine A
I'm able to ping machine C from machine B
I'm NOT able to ping machine B from machine C
A and C can ping each other

(In reality I'm trying to hot-sync my palm over the network, which isn't
working. Hence I tried pinging to see if the connections were working -
which they aren't)

Setting configuration:

Machine A - Set up in a workgroup.

Machine B - This is a laptop, set up for my work domain. However, I'm
ovbiously NOT loging in into the domain at home. This machine also has a
VPN installed, but when I tried running the above test the VPN was NOT
running. The VPN also installed a "deterministic network enhancer" protocol
on my adapter. I unchecked the box in the Network settings when I ran the
above test.

Machine C - Set up in the same workgroup as A

Network stuff - I tried the ping using IP addresses as well as NETBIOS
names. Pings FROM B work both ways; pings TO B never work.

Can someone explain what may be going on?

Thanks!
CG

 

[Chuck]

I have two Win2K machines (A and B) and an XP machine (C) on a home network
(via a Linksys router)

I'm able to ping machine A from machine B
I'm NOT able to ping machine B from machine A
I'm able to ping machine C from machine B
I'm NOT able to ping machine B from machine C
A and C can ping each other

(In reality I'm trying to hot-sync my palm over the network, which isn't
working. Hence I tried pinging to see if the connections were working -
which they aren't)

Setting configuration:

Machine A - Set up in a workgroup.

Machine B - This is a laptop, set up for my work domain. However, I'm
ovbiously NOT loging in into the domain at home. This machine also has a
VPN installed, but when I tried running the above test the VPN was NOT
running. The VPN also installed a "deterministic network enhancer" protocol
on my adapter. I unchecked the box in the Network settings when I ran the
above test.

Machine C - Set up in the same workgroup as A

Network stuff - I tried the ping using IP addresses as well as NETBIOS
names. Pings FROM B work both ways; pings TO B never work.

Can someone explain what may be going on?

Thanks!
CG

CG,

I'd bet that the domain setup of Machine B is related to the problem.
What we have to figure out is exactly what is the root cause of the
problem.

I use basic problem solving skills - someone else here may
instinctively know the cause from direct experience. Let's see what
happens. Should be fun.

Does Machine B maybe have a firewall - one that lets you send OUT
pings but drops INcoming pings?

Please first switch network cables between machines A and B. Repeat
tests. You are running machine B wired right?

Please expand upon "can ping" vs "can't ping"
Are you pinging by machine name or ip address?
Is your "can't ping" similar to Case 1 or 2 (below)?

Please provide output from "ipconfig /all" for all three machines.

####### Case 1:

Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

C:\Documents and Settings\Example1>ping Example2
Ping request could not find host Example. Please check the name and
try again.

####### Case 2:

C:\Documents and Settings\Example1>ping 192.168.203.11

Pinging 192.168.203.11 with 32 bytes of data:

Request timed out.
Request timed out.
Request timed out.
Request timed out.

Ping statistics for 192.168.203.11:
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),

####### End Cases

Cheers,

Chuck
I hate spam - PLEASE get rid of the spam before emailing me!
Paranoia comes from experience - and is not necessarily a bad thing.

 

[Rediranch]

Check here - http://www.sysopt.com/forum/forumdisplay.php?
s=&forumid=10

There are some "Stickies" as they call them, that might
help.

 

[Michael Johnston [MSFT]]

This sounds like inbound ICMP is being filtered on B. Check for firewall software. What OS is machine b running? If it's XP make
sure that ICF is disabled. Also, try stoping the IPSec service in services. Your domain may apply IPsec policies that could
cause this behavior. If you stop this service, this removes those policies. On W2k it's called "IPsec policy agent. On XP it's
called "IPSec Services".

Thank you,
Mike Johnston
Microsoft Network Support
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[Carlos G]

I finally tracked it down. Apparently the VPN has a stateful firewall which
is executed via a service. So even if the VPN software itself is not
running, the service is. I stop the service and everything is happy.
Unfortunately, stopping the service appears to be the only way around the
problem. How annoying that the VPN software affects my computer even when
I'm not using it!

CG

This sounds like inbound ICMP is being filtered on B. Check for firewall

software. What OS is machine b running? If it's XP make

sure that ICF is disabled. Also, try stoping the IPSec service in

services. Your domain may apply IPsec policies that could

cause this behavior. If you stop this service, this removes those

policies. On W2k it's called "IPsec policy agent. On XP it's

called "IPSec Services".

Thank you,
Mike Johnston
Microsoft Network Support

rights. Use of included script samples are subject to the

terms specified at
http://www.microsoft.com/info/cpyright.htm

Note: For the benefit of the community-at-large, all responses to this

message are best directed to the newsgroup/thread from