I having an issue with 2 of my SErver 2008 servers. One is a terminal server and the other is an Exchange 2007 SP1 Mailbox server. I am having issues that are resolved by deleting the arp cache on the servers. For exchange - I have a terminal server at one of our branch offices and this morning, the exchange server was unable to ping the terminal server. Every other machine in the enterprise is able to ping the terminal server, just not the exchange server. I can ping the terminal server from the switch the exchange server is plugged into and from the router that switch uses as it's gateway. Once I cleared the arp cache, the exchange server could then ping the terminal server. I have the same issue on a terminal server and for printing. I cannot ping printers every now and then from the TS, but can from my client. Clearing the arp cache on the terminal server resolves this issue. If anyone has any ideas on how to troubleshoot this, that would be great. Thanks, ZachZach Smith

In Windows Vista and Windows Server 2008, the ARP cache timeout is not random value between 15 seconds and 45 seconds. The system should update ARP quickly enough that we don’t need to clear it. When the issue occurs, type "arp –a >>arp.txt", try to clear ARP and run "arp –a >>arp.txt" again. Paste arp.txt here for research. Thanks.This posting is provided "AS IS" with no warranties, and confers no rights. Please remember to click "Mark as Answer" on the post that helps you, and to click "Unmark as Answer" if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

The issue just occurred. Arp Cache BEFORE I cleared it - server cannot ping an ip address of 10.153.3.1 nterface: 10.1.50.77 --- 0xb Internet Address Physical Address Type 10.1.50.1 00-0d-28-02-f8-4b dynamic 10.1.50.4 00-14-38-bf-3e-6d dynamic 10.1.50.5 00-0b-cd-cb-1b-23 dynamic 10.1.50.10 00-07-0e-11-de-c3 dynamic 10.1.50.11 00-15-5d-32-6d-02 dynamic 10.1.50.14 00-0b-cd-ff-48-0c dynamic 10.1.50.17 00-11-85-e8-6d-cb dynamic 10.1.50.18 00-50-8b-c7-5a-65 dynamic 10.1.50.20 00-0d-9d-93-2c-09 dynamic 10.1.50.22 00-0d-9d-93-2c-19 dynamic 10.1.50.24 00-50-8b-32-21-e3 dynamic 10.1.50.29 00-0d-9d-93-2b-f5 dynamic 10.1.50.33 00-08-02-ed-ef-36 dynamic 10.1.50.34 00-50-8b-b8-57-c6 dynamic 10.1.50.49 00-0d-9d-57-bf-d3 dynamic 10.1.50.64 00-15-60-0b-b8-7c dynamic 10.1.50.68 00-30-f1-53-97-4e dynamic 10.1.50.78 00-1a-4b-ce-06-1c dynamic 10.1.50.79 00-1a-4b-ce-b5-c5 dynamic 10.1.50.162 00-1f-29-e0-6e-5e dynamic 10.1.50.167 00-1f-29-e0-34-6e dynamic 10.1.50.177 00-15-5d-32-a2-03 dynamic 10.1.50.255 ff-ff-ff-ff-ff-ff static 224.0.0.252 01-00-5e-00-00-fc static Arp Cache AFTER I cleared it. Server can now ping 10.153.3.1 Interface: 10.1.50.77 --- 0xb Internet Address Physical Address Type 10.1.50.1 00-0d-28-02-f8-4b dynamic 10.1.50.4 00-14-38-bf-3e-6d dynamic 10.1.50.17 00-11-85-e8-6d-cb dynamic 10.1.50.18 00-50-8b-c7-5a-65 dynamic 10.1.50.24 00-50-8b-32-21-e3 dynamic 10.1.50.33 00-08-02-ed-ef-36 dynamic 10.1.50.49 00-0d-9d-57-bf-d3 dynamic 10.1.50.78 00-1a-4b-ce-06-1c dynamic 10.1.50.79 00-1a-4b-ce-b5-c5 dynamic Zach Smith

Hi, Thank you for update. 10.153.3.1 was not listed in this table, it sent the traffic to the default gateway. Which is your default gateway? Please also let us know your network topology, run "ipconfig /all >>ip.txt" and paste here. When the issue occurs again, let’s try to monitor the traffic with Microsoft Network Monitor. http://www.microsoft.com/downloads/details.aspx?FamilyID=983b941d-06cb-4658-b7f6-3088333d062f&displaylang=en 1. When it occurs, run Network Monitor and start capturing. 2. Ping 10.153.3.1. Stop the capturing, save the result and upload the file to Windows Live SkyDrive (http://www.skydrive.live.com/). If you would like other community member to analyze the report, you can paste the link here, if not, you can send the link to tfwst@microsoft.com. Clear arp cache. 3. Start a new capture, ping 10.153.3.1 and save and upload the capture file. Thanks.This posting is provided "AS IS" with no warranties, and confers no rights. Please remember to click "Mark as Answer" on the post that helps you, and to click "Unmark as Answer" if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

Will do with the network monitor. As an FYI - I did log into the switch the server is connected to and the default gateway of the switch and both could ping the ip address in question - only this server could not. Thanks for the help ZachZach Smith