[Today’s post comes to us courtesy of James Frederickson and Shawn Sullivan from Commercial Technical Support]
We have seen an increase of instances where customers are experiencing various networking problems because they have altered the networking topology by installing multiple NICS or assigning multiple IPs to their single NIC. Some of the more common issues we have seen with this scenario include, but are not limited to:
· Slow or complete loss of file share/network login access
· Problems with Outlook connectivity (mailbox login, Autodiscover, OAB, Free/Busy, OOF assistant, Outlook Anywhere)
· Issues accessing web sites (OWA, RWW, Sharepoint, Connect)
· Issues with service startup, particularly Exchange.
· The server hangs at “Applying Computer Settings” upon boot.
· Inability to complete the SBS networking wizards (IAMW and CTIW)
SBS 2008 (Server 1 in Premium Edition) is supported by Microsoft only in a single network card environment with a single IP address. If multiple NICs are detected during the initial SBS setup, all but one will be disabled. This is because the integration between the various components included with the product has been designed to depend on this basic topology. This, in turn, simplifies the deployment of the product. Other configurations, although supported and perfectly legitimate on Windows Standard edition, would be considered unsupported in SBS 2008. Microsoft technical support may require that the server is brought back into a supported scenario before troubleshooting can begin. For more information regarding supported network topologies and SBS, see the following post.
To return the server to a functioning and supported state, begin by running the SBS 2008 BPA. This will check for and notify you of any network configuration settings that require attention:
1. Multiple NICs are installed and active. Or multiple NICs are installed, but only one is plugged in.
To fix this, open Network Connections from the Control Panel, or type ncpa.cpl from the Run command.
**Note** It is critically important to know which IP addresses your services (DNS, IIS, SMTP, Terminal Services, etc) currently are listening on before you make any changes to your TCP/IP configuration. You could easily render a critical service completely unbound from the network.
Right-click and disable all but the primary adapter. If you decide remove and uninstall the additional adapters, please read the following SBS blog Device Manager may seem to hang while uninstalling a NIC.
You will also need to verify the binding order of your NICs by clicking on Advanced > Advanced Settings menu. Your enabled NIC must be first in the list and must have both File/Print sharing and Client for Microsoft Networks enabled:
2. Multiple IPs are assigned to the NIC.
As stated before, SBS 2008 is designed to only have a single IP address on a single network adapter. The NIC must use a private IP address with a 255.255.255.0 subnet mask. The following IP ranges are supported:
- 10.0.0.0 – 10.255.255.255
- 172.16.0.0 – 172.31.255.255
- 192.168.0.0 – 192.168.255.255
Remove any additional IP addresses that you have bound to the NIC. Be careful and verify which IP address(es) your services are listening on, changing them if necessary, beforehand.
A note about NIC teaming:
We periodically encounter servers with NIC teaming enabled. When configured properly, teamed NICs will logically act as a single NIC with a single IP address and provide fault tolerance if one fails. However, this still falls into an unsupported network topology on SBS 2008 and you may be asked by Microsoft technical support to break the team as part of troubleshooting. You can find this documented as well in the SBS 2008 Release Documentation under the section “The Windows Small Business Server 2008 networking wizards do not support network teaming”.