A TCP/IP network requires an Ethernet device be assigned an IP address to identify it as a host on the network. Typically, a host name and routing information are also required.
Larger TCP/IP networks include dedicated servers to provide IP addressing and packet routing protocols, while smaller networks may configure these functions on every host on the network.
The Ethernet TAP probe is an Ethernet device that is configured by DHCP (default) or by using the built-in commands to set a static network configuration for your particular network environment.
The Ethernet TAP probe's default operation is to use the DHCP protocol to automatically acquire its network configuration. If necessary, you can change its network configuration by doing the following.
Each Ethernet TAP probe has a unique Ethernet address in the form 00:00:F6:D0:B6:48. The Ethernet address of your probe is printed on a label on its underside.
To act as a host on a TCP/IP network, an Ethernet device must also have a unique IP address (e.g., 10.189.85.42) and, for convenience, a host name (e.g., testdev1).
The Ethernet TAP probe acts as a host on a TCP/IP network, as does each workstation that accesses it using a debugger.
An Ethernet packet may be sent to a host using either the host IP address, or the host name, or the host Ethernet address. A packet bearing a host IP address is delivered automatically, but a host name or host Ethernet address must be resolved to the corresponding host IP address before the packet can be delivered.
A host such as an Ethernet TAP probe is uniquely identified on a TCP/IP network by the following address information:
A subnet mask of 255.255.255.0 applied to the IP address above defines host number 42 on the 10.189.85 subnetwork.
Name resolution is the process of resolving a host name to its IP address. In larger networks, this is accomplished by a Name Server, typically using the DNS protocol. Some older Windows installations (NT4 and earlier) may use Windows Internet Name Service (WINS).
If you configure your Ethernet TAP probe with a static IP address, an entry must be made in your DNS and/or WINS database file designating the host name and IP address of the Ethernet TAP probe.
In network environments that assign network parameters via DHCP, there may be an automated link between the DHCP server and the DNS server such that the DNS server automatically receives an update with the Ethernet TAP probe's host name. This readily works where both the Windows DHCP server and Windows DNS server are used. It may be made to work in UNIX environments as well, using a protocol known as Dynamic Domain Name Service (DDNS); see your UNIX reference documentation for more information.
For smaller networks, each workstation does its own name resolution through a simple text file. In UNIX environments the file is known as /etc/hosts. In Windows environments the file is known as hosts and is typically found in the %system_root%\system32\drivers\etc\ directory.