Can't ping XP pc, but can ping from XP pc

[bannerman1]

Hi,
A PC called PC1 (Dell Latitude C800, XP SP2) on our Windows 2000 domain can't be pinged. It can however ping other PCs, routers etc. Also an SSH server on this PC doesn't work. There is no problem browsing the internet from this PC.

What I've tried:
Turning off Windows Firewall and any other firewall.
Renaming the PC in the domain and changed it's IP address.
Moved the PC to a different LAN (different address on a seperate switch).
Used a different network card (I tried the following steps using both network cards with the same results).


While unsuccessfully pinging PC1 from another computer I've run Ethereal in promiscious mode on PC1. PC1 does not detect any incoming pings or any incoming ICMP packets at all. It will detect outgoing ones if I ping from PC1.

After attempting to ping PC1 from another PC I can see the MAC address in the ARP cache of the PC I've just tried to ping from.

The real problem here is that I can't connect to this PC using SSH but I'd say the ping issue is related.

Has anyone any ideas what is causing this issue??

[faulkner132]

Are you pinging it from the local IP or from the local machine name?

While troubleshooting I would deal strictly with the local IP so DNS issues are not involved.

Edit:
Also try doing this from another PC (not the problem PC, but any other one) to see where the packets are getting hung up:

tracert [local IP of problem machine]

[ITlover]

Bannerman,

Try this on PC1,go to Windows Firewall-----> Advance-----> In this Advance tab you will see a Settings button at "ICMP" , just click this button and put a check on "Allow incoming echo request".
And "Allow incoming router request".

If you are trying to ping PC1 from your Local Network or from another network connected via router.

I hope this should solve the problem.

[ITlover]

Keep your windows firewall on if you are concerned about the network security

[glc]

IT, it's not a XP firewall issue, the poster says that disabling it did not help.

[bannerman1]

Hi All,
I've pinged it using the IP address and the DNS name. I usually just stick with IP address though.

Tracert xx.xx.xx.49 comes up with...
C:\Documents and Settings\mememe>tracert xx.xx.xx.49

Tracing route to 156.24.240.49 over a maximum of 30 hops

1 * * * Request timed out.
2 * * * Request timed out.

Not much help here as the PCs are connected to the same switch.

I have the firewalls turned off. That's not to say I've ruled out Windows Firewall.... Because Ehtereal does not pick up the paclets while in promiscious mode does that mean the packets are not reaching the network card? Surely Windows firewall will not stop Ethereal from detecting packets on the Network card? If it can and Windows Firewall is having a problem (i.e. still working at some level even though it appears to be off) it may be the cause.

I'm going to try Ethereal on a XP SP2 PC to see if incoming pings are detected with Windows Firewall on.

In the mean time has anyone any other suggestions?

[bannerman1]

I've just turned on Windows Firewall on another XP SP2 PC and run Ethereal in promiscious mode on it. The firewall has the default settings with ICMP echo requests blocked. When pinging from another PC Ethereal still picks up the requests even though the Firewall is not accepting them.

This is actually what anyone would have expected but I think it does rule out Windows Firewall behaving badly as being the issue.

I'm going to try re-applying SP2 to see if that has an effect.

[ITlover]

You mean to say that the PC on which the echo request is blocked still responds to the ping command that you send from another PC?

[bannerman1]

No, that's not actually what I said. The PC with the firewall on is not replying to the echo requests... because the firewall is set to block ICMP packets. Ethereal running on this PC however sees the ICMP packets coming in over the network.

[faulkner132]

Do you have any TCP filtering on your network card?

Control Panel > Network Connections > Network Card Properties > Internet Protocol (TCP/IP) > Properties > General Tab > Advanced > Options Tab > TCP/IP Filtering > Properties

Filters here would cause all network traffic on specified ports to be dropped, regardless.

[bannerman1]

I checked, there's no filtering, but good idea all the same.

[faulkner132]

Is it possible you could try using a different network card just to rule hardware out?

[ITlover]

Originally Posted by bannerman1 No, that's not actually what I said. The PC with the firewall on is not replying to the echo requests... because the firewall is set to block ICMP packets. Ethereal running on this PC however sees the ICMP packets coming in over the network.

Well yes, it will not reply if the ICMP(Internet Control Messeging Protocol) is blocked in its win firewall settings.

Thats what I was saying, the computer(PC1) that you are trying to ping might have ICMP blocked in its win firewall settings and this could most probably the reason why it could not reply to the ping request from another PC.


But as far as I know you will be able to ping other computers from PC1 if other computers have ICMP echo request unblocked in their win Firewall settings.

Yes you will see the network traffic coming into your computer and you will see ICMP packets flowing into your network and your Computer might be recieving the ping request from any PC but it might not be able to reply because the ICMP echo request is blocked in its fire wall settings.

For example sometimes it happens in Telephone connections, it works 1 sided, If I give you a call and you can hear me but sometimes it happens that I cannot hear you because you cannot reply me.

I hope you are geting my point.

[faulkner132]

Originally Posted by bannerman1 What I've tried: Turning off Windows Firewall and any other firewall.

ITLover, again, firewalls (Windows or any other) are not a factor here.

[telegramsam]

Have you set up a user account in the Win2k machine for the XP pc? Win2k doesn't just network like XP does. I suppose it should still respond to a ping, but you won't be able to access it unless you set that up.

Check your IP settings and make sure your IP scheme is the same--and the subnet masks should match as well.

[glc]

User accounts have nothing to do with pings.

[bannerman1]

Faulkner - I used a different network card, with the same results.

telegramsam - ??? What Win 2K machine? ??? Read the problem and the troubleshooting that was done already, cheers ;-)

glc - I agree, user accounts have nothing to do with pings

Itlover- PC1 (the problem PC) is not receiving ICMP packets as far as I can tell, the packet sniffer (Ethereal, which uses Winpcap) I used on PC1 did not detect incoming ICMP packets. This packet sniffer should detect incoming ICMP packets regardless of firewall settings on the PC.

I've just had a thought, I should show definitivly if packets are reaching the network card of PC1.
When I'm back in the office Monday I'll connect PC1 to a hub and I'l connect the hub to the LAN.
I'll connect "PC2" to the hub which will be running Ethereal.
I'll ping PC1 from another PC on the LAN and see if Ethereal on PC2 sees the packets.

If PC2 does detect packets it will show that there's something funny going on at a low level on PC1. This is pretty much what I'm expecting to happen from what I've seen already. The trick will be to fix this problem without a rebuild of PC1!!

I'll get back to this Monday...

[ITlover]

Well,I think this will be an alternate way to detect the problem.

Can you remotely connect to PC1 from any other PC in your local network? If you can, then their is nothing wrong with connection between your PC1 and other Computers.

Have you checked the network status and performance on your PC by pressing Alt+Ctrl+Del?

Glc, in this kind of problem, should the NIC card be replaced or not because banner doesnot have problem using internet service ,he is only having problem with ping?

[glc]

Internet uses TCP/IP so if the Internet works, the NIC is fine.

[ITlover]

Then what could be the problem with his system, let us see what happens after he does that experiment.

Glc, if the PC1 is able to ping other Computers, does this also proves that its NIC card is running fine?

[ITlover]

What does this TCP/IP(Transmission Control Protocol/Internet Protocol) filtering do? Does it filter any unwanted incoming data and programs from internet to your computer?
Does it also filter the spywares and viruses that could enter our system?

[bannerman1]

ITlover - I've already ruled out the NIC as the problem as I replaced it with another NIC and observed the same issues.

The problem is not with connecting to other PCs, but with not being able to ping this PC and that the SSH server that needs to run on this PC won't accept connections. I can connect to other PCs. I'm working on the assumption that the 2 issues are related, by fixing the ping problem the SSH connection problem will go too (hopefully).

[ChoboSeki]

Originally Posted by glc IT, it's not a XP firewall issue, the poster says that disabling it did not help.

I've noticed in a lot of cases that disabling the Windows XP Firewall doesn't really help much unless you actually disable the service manually:

Start > Run > CMD

Net Stop SharedAccess

[bannerman1]

Problem solved!

Solution: There was a firewall installed that the user and I was not aware of. It came as part of a package that didn't say that a firewall was being installed.

I found it by constantly pinging the PC and stopping services relating to user installed softeare one by one. Suddenly after stopping the right service ping replys came in!

Looking at it now, my troubleshooting should have involved this at an earlier stage. It's interesting to note that firewall software IS capable if intercepting network traffic so that Winpcap (Ethereal etc.) cannot detect the traffic. I always assumed that if the traffic was hitting the network card Winpcap would pick it up every time.

Thanks everyone for you're time and effort with this

[glc]

Isn't it amazing how nuts it can get when you rule something out that really was the problem?