Computers in same network can't ping each other

[packdragon]

We have a bunch of computers on the same subnet, same domain. ComputerA cannot ping ComputerB and viceversa. However my computer (also in the same network) can ping them both, and so can a coworker's. I can't think of a reason why that would be? ComputerA can ping everyone else's machine, and so can ComputerB. They just can't ping each other. Anyone have a clue?

- Zoe, that's ZOH-EEE, get it right please
- Just a little ol' MCP at Solien Technology
-

http://www.solien.com

 

[Davetoo]

How are you pinging? By machine name or by IP addy? If by machine name, suspect would be TCP/IP on the machines.

I'm Certifiable, not certified.
It just means my answers are from experience, not a book.

 

[h4nym]

Are you DHCPing the ipconfig to all three? A, B & yours? If not then check IP address, subnet mask and DNS settings on each of A & B.

Can A&B ping other machines on the LAN, just not that particular one?

Echoing Lander's post - if it's by address/computer name, then suspect DNS, and make sure that "Register this connection in DNS" is checked in the TCP/IP properties of A & B.

If you're trying to ping by IP address, then I assume you're using fixed IP addressing, in which case have a close look at your subnetting on A & B.

Finally, check your ARP cache and try flushing your DNS cache - start from a clean sheet.

hth

H

Hany Mustapha
Excellent Technology Solutions in the UK -

http://www.ElectronicWorkplace.com

 

[packdragon]

Those two computers are using DHCP. When pinging by name, the name does resolve into an IP address, but the request times out. Attempting to ping directly using the IP address given yields the same results. Both A and B are able to ping other machines on the LAN, just not each other.

What is ARP cache?

Thanks for the tips on what to check. I'll have to see if I can find anything.

- Zoe, that's ZOH-EEE, get it right please
- Just a little ol' MCP at Solien Technology
-

http://www.solien.com

 

[AJP69]

Post the output of IPconfig /all for the three machines

(c:\IPConfig /all >>Post.txt)

There is either a config error or a hardware fault.

 

[ksukenny]

ARP is address resolution protocol. to delete the arp cache go to a command prompt and type arp -d

 

[packdragon]

Got busy for awhile and didn't have time to post the ipconfig results, but the problem persists so I will post them now! I have not tried deleting the ARP cache yet. Would I need to do that on both problem machines?

Here are the ipconfig results from three machines. The first two are the problem machines that cannot reach each other, the third is a computer that can reach both, and both computers can ping it right back.

PROBLEM COMPUTER 1 (Win2000 Pro)
----------------------------------
Windows 2000 IP Configuration
Host Name . . . . . . . . . . . . : jennifer
Primary DNS Suffix . . . . . . . : sequoiasoft.solien.com
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : sequoiasoft.solien.com
zooom.solien.com

Ethernet adapter Local Area Connection:
Connection-specific DNS Suffix . : sequoiasoft.solien.com
Description . . . . . . . . . . . : Intel(R) PRO/100 VE Network Connection
Physical Address. . . . . . . . . : 00-03-47-39-C3-12
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . . . . . . . . . . : 10.1.1.214
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 10.1.1.1
DHCP Server . . . . . . . . . . . : 10.1.1.33
DNS Servers . . . . . . . . . . . : 10.1.1.6
10.1.1.33
Primary WINS Server . . . . . . . : 10.1.1.6
Lease Obtained. . . . . . . . . . : Tuesday, August 05, 2003 3:49:16 PM
Lease Expires . . . . . . . . . . : Thursday, August 07, 2003 3:49:16 PM

PROBLEM COMPUTER 2 (WinXP Pro)
-------------------------------
Windows IP Configuration
Host Name . . . . . . . . . . . . : zero
Primary Dns Suffix . . . . . . . : sequoiasoft.solien.com
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : sequoiasoft.solien.com
zooom.solien.com

Ethernet adapter Local Area Connection 2:
Connection-specific DNS Suffix . : sequoiasoft.solien.com
Description . . . . . . . . . . . : 3Com EtherLink 10/100 PCI For Complete PC Management NIC (3C905C-TX)
Physical Address. . . . . . . . . : 00-01-03-22-BC-31
Dhcp Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . . . . . . . . . . : 10.1.1.235
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 10.1.1.1
DHCP Server . . . . . . . . . . . : 10.1.1.33
DNS Servers . . . . . . . . . . . : 10.1.1.33
Primary WINS Server . . . . . . . : 10.1.1.6
Lease Obtained. . . . . . . . . . : Tuesday, July 15, 2003 2:06:27 PM
Lease Expires . . . . . . . . . . : Thursday, July 17, 2003 2:06:27 PM

Ethernet adapter Local Area Connection:
Media State . . . . . . . . . . . : Media disconnected
Description . . . . . . . . . . . : 3Com EtherLink 10/100 PCI TX NIC (3C905B-TX)
Physical Address. . . . . . . . . : 00-01-02-36-A4-22

NORMAL COMPUTER (Win2000 Pro)
------------------------------
Windows 2000 IP Configuration
Host Name . . . . . . . . . . . . : eileen
Primary DNS Suffix . . . . . . . : sequoiasoft.solien.com
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : sequoiasoft.solien.com

Ethernet adapter Local Area Connection:
Connection-specific DNS Suffix . : sequoiasoft.solien.com
Description . . . . . . . . . . . : 3Com EtherLink 10/100 PCI For Complete PC Management NIC (3C905C-TX)
Physical Address. . . . . . . . . : 00-01-03-1A-3F-37
DHCP Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . . . . . . . . . . : 10.1.1.219
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 10.1.1.1
DHCP Server . . . . . . . . . . . : 10.1.1.33
DNS Servers . . . . . . . . . . . : 10.1.1.6
10.1.1.33
Primary WINS Server . . . . . . . : 10.1.1.6
Lease Obtained. . . . . . . . . . : Wednesday, August 06, 2003 9:37:50 AM
Lease Expires . . . . . . . . . . : Friday, August 08, 2003 9:37:50 AM



- Zoe, that's ZOH-EEE, get it right please
- Just a little ol' MCP at Solien Technology
-

http://www.solien.com

 

[wbg34]

Check the cables on pc#2
Ethernet adapter Local Area Connection:
Media State . . . . . . . . . . . : Media disconnected

 

[dholbrook]

Zoe,

Look at the information you provided:

Computer one:
DHCP Server . . . . . . . . . . . : 10.1.1.33
DNS Servers . . . . . . . . . . . : 10.1.1.6
10.1.1.33
Primary WINS Server . . . . . . . : 10.1.1.6

COmputer two:
DHCP Server . . . . . . . . . . . : 10.1.1.33
DNS Servers . . . . . . . . . . . : 10.1.1.33
Primary WINS Server . . . . . . . : 10.1.1.6

Normal COmputer:
DHCP Server . . . . . . . . . . . : 10.1.1.33
DNS Servers . . . . . . . . . . . : 10.1.1.6
10.1.1.33
Primary WINS Server . . . . . . . : 10.1.1.6

Change the DNS on Server two to 10.1.1.6 first, and add 10.1.1.33 as a second DNS and see if that fixes the problem. Then I would go look at the DNS server at 10.1.1.33 and see what is wrong on that server. System one and three will both go to 10.1.1.6, so probably do not ever get to 10.1.1.33. System two does not have that option, as there is no second DNS to go to. Name resolution is being provided by the WINS/DNS server at 10.1.1.6, so it appears to be working correctly.

HTH

David

 

[packdragon]

I actually did notice that and did exactly as you suggested. I put 10.1.1.6 first and .33 second, but that didn't fix it either. Would I have to flush/register DNS? I'll give that a try. But the thing is, it doesn't appear to be a DNS issue because when attempting to ping by name, the name does resolve to an IP address. It just times out. Pinging by IP times out also.

The cables are fine. It can reach all other computers. What you see there is the internal NIC that was disabled and currently unused.

Thanks for your input guys, I really appreciate the suggestions... any more tips?

- Zoe, that's ZOH-EEE, get it right please
- Just a little ol' MCP at Solien Technology
-

http://www.solien.com

 

[ksukenny]

from the command line type "route print" and see what it lists for the ip address of the computer you can't get to

 

[dholbrook]

After you change the computer DNS configuration, run ipconfig /release, then ipconfig /renew to flus the old data off the adapters.

The system set up different is correctly pointing at the WINS server, so the name resolution is working that way.

HTH

David

 

[packdragon]

I did the ipconfig /release and /renew, after which I tried to ping ZERO again. Still timing out. I had also tried assigning it an IP address instead of using DHCP. Same result. The main problem that this is causing is that ZERO is a developer's machine and he regularly posts changes to the development site hosted on his machine. The project manager has to be able to browse it to verify the changes are correct, but can't even access the website that is hosted there. She has to go to a different machine to do it.

I'm learning a lot of network troubleshooting steps here, I really appreciate the efforts!

Here are the results of the route print:
============================================================Interface List
0x1 ........................... MS TCP Loopback interface
0x1000003 ...00 03 47 39 c3 12 ...... Intel(R) PRO/100 VE Network Connection
============================================================
Active Routes:
Network Destination Netmask Gateway Interface Metric
0.0.0.0 0.0.0.0 10.1.1.1 10.1.1.214 1
10.1.1.0 255.255.255.0 10.1.1.214 10.1.1.214 1
10.1.1.214 255.255.255.255 127.0.0.1 127.0.0.1 1
10.255.255.255 255.255.255.255 10.1.1.214 10.1.1.214 1
127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1 1
224.0.0.0 224.0.0.0 10.1.1.214 10.1.1.214 1
255.255.255.255 255.255.255.255 10.1.1.214 10.1.1.214 1
Default Gateway: 10.1.1.1
============================================================Persistent Routes:
None


- Zoe, that's ZOH-EEE, get it right please
- Just a little ol' MCP at Solien Technology
-

http://www.solien.com

 

[dholbrook]

How about a really dumb question.... has he taken this system out of the domain? Sorry, I get really suspecious about developer machines. I have even had one developer remove the built in administrators account on his system!

At this point, I would try removing the net card from the system hardware, rebooting and let the system re-find the hardware (remove it from the hardware configuration in control panel, system, hardware, device manager, network devices, etc.). Then do ipconfig /all again on this system and make sure it has all the right values, then try to ping itself, then the other systems, first by ip then by name.

Hth
David

 

[packdragon]

Heh, some developers do get a little crazy. I'm pretty sure he wouldn't do anything like that, he's a "good boy" who usually asks before doing anything remotely drastic. Plus no other machines appear to have trouble reaching his. This weird problem is SOLELY between these two machines.

I just peered in the back of the JENNIFER machine and noticed that there actually was NOT a second NIC installed in there like I first thought. So I went to check out what the second LAN connection was. It belongs to "PGP Virtual Identity Adapter". I know we regularly send sensitive material to clients so PGP is necessary... but what is this adapter? Could it be the cause? I don't want to mess up her PGP setup, since I'm not too familiar with it.

- Zoe, that's ZOH-EEE, get it right please
- Just a little ol' MCP at Solien Technology
-

http://www.solien.com

 

[Seumas13]

Hey, ZOH-EEE -

Question: Are you possibly using Cascaded Hubs?

Cascaded Hubs work well if all Clients only need to talk with the Server(s), but not so well if they need to talk to each other.

I've seen this sort of thing happen when there are too many Hubs between PC-A & PC-B.
PC-C is somewhere in the middle and has only two Hubs between it and each of the others, but PC-A & PC-B have four (or more) hubs between them.

Just a thought...

Seumas

 

[packdragon]

No cascading hubs that I know of. All the computers in the domain are connected to each other through a switch. We even tried moving their connections to different ports in the switch, but it made no difference. Thanks for the thought though!

- Zoe, that's ZOH-EEE, get it right please
- Just a little ol' MCP at Solien Technology
-

http://www.solien.com

 

[dholbrook]

Zoe,

The route print looks correct, provided the machine local address is the 10.1.1.214, the network address is 10.1.1.0, and the gateway is 10.1.1.1. What does the route print give from the second system?

Just a thought, it is possible someone has fiddled with the IP addresses and you now have duplicates in the network if you are assigning hard addresses. You can try changing the IP addresses for both systems, update the DNS,and see if this resolves the issue.

As a test, disconnect one of the problem systems from the network, ping its address from your third system, and see if your still get a reply. If you do, then change the addresses on that system and then try again to see if it can now ping the other problem system. Repeat with the second system if it still can not see the first (A can now see B, but B still can not see A, etc.).

Just an idea,

David

 

[mtnbkr]

Aloha, Zoe -

Since you've verified that both "victim" machines have connectivity to the network and are able to communicate with your server, I would recommend examining your switch for misconfigured VLAN entries - I've had machine that were on separate VLANs that could see the servers, but not one another. Good Luck!

 

[unixgy]

Hello Everyone.

I have a NetGear Firewall/Router hooked up to my cable modem (192.168.1.1). Here is my network setup:

Windows 2000 Server box with two NICs (192.168.1.2, 172.168.1.1). Netmask 255.255.255.0 Default Route 192.168.1.1 for both NIC's.

Windows 98 Box (192.168.1.3) Netmask 255.255.255.0 Default Route 192.168.1.1

Windows 2000 Pro Box (172.168.1.2) Netmask 255.255.255.0 Default Route 172.168.1.1

Does anyone have a step-by-step procedure for me to setup my Windows 2000 Server box as a Router for me to access the 192 network and the Internet from my Windows 2000 Pro box?

I would then like to add a Firewall to the Windows 2000 Server box to add a layer of protection to my 172 network.

Any help is GREATLY appreciated.

Thanks, in advance.

Unixgy