HP Network Direr Software Products manual Key Considerations

Key Considerations 659

Why Errors Can Occur When you are adding a server it is necessary to enter a unique non-blank When Adding a name and either a valid DNS name or a valid IP address. If you choose to Server enter an IP address it must not be a broadcast IP address. If any of these

conditions are not met then the wizard will not allow the server to be added and an appropriate warning message will be displayed.

3Com Network Director will resolve DNS names by using the DNS servers that the PC it is running on is configured to use and that 3Com Network Director was able to contact when it was started. This means that you will be unable to add servers by DNS name if any of the following occur:

■3Com Network Director was unable to contact any of the configured DNS servers when it was started.

■3Com Network Director was only able to contact some of the configured DNS servers when it was started and none of the DNS servers contacted are able to resolve the DNS name.

■It is not possible to contact any of the configured DNS servers while you were adding servers.

■It is only possible to contact some of the configured DNS servers while you were adding servers and none of the DNS servers that can be contacted are able to resolve the DNS name.

If it was not possible to contact a DNS server when 3Com Network Director was started but you are now able to do so, you will need to restart 3Com Network Director before it will use the DNS server.

Potential Hazards Blocking traffic to and from servers is a powerful feature that prevents When Blocking Traffic access to particular resources. However, if you select the wrong servers to

To and From Servers be blocked then this can cause severe problems on your network.

Whenever you attempt to block traffic to and from a server it is important that you check that:

■The IP address of the server you wish to block does not belong to a server that is critical to your network infrastructure, such as a DHCP or RADIUS server. Blocking IP addresses such as these may prevent your network infrastructure from functioning correctly.