HOSTS File 

is used by the Network Monitor to translate the MAC addresses reported by the LanProbes to the proper host names as described inside the /etc/hosts file.

HOSTS contains one-line entries for each network system interface.

Each entry in the file HOSTS consists of the following elements:

IP_address

the IP address of the network interface

hostname

the corresponding host name

MAC_address or NOT_FOUND

the MAC address of the network interface or no MAC address if the network interface was not reporting a MAC address to the SNMP request of the automatic configuration tool.

An entry looks like this example:

IP_address hostname MAC_address|NOT_FOUND

It can be difficult to create the translation file HOSTS manually. You should therefore use the automatic configuration tool readhosts in the directory /usr/sap/<SAP_SYSTEM_NAME>/SYS/exe/run . The automatic configuration tool can find the MAC address of a network interface if it has the IP address of this network interface.

The IP addresses of the requested MAC addresses are provided as a command line input to the tool. To execute the automatic configuration tool, specify the program in the command line using the the following syntax:

$readhosts seed_file

In this example, seed_file is the name of a file whose format is similar to the /etc/hosts file. Every line in this file is the IP address and the host name of the network interface for which the MAC address is needed. seed_file is either the full path name of the seed file or a local file name of a seed file in the current execution directory of the readhosts tool.

A line in seed_file could look like this:

IP_address hostname

If the automatic configuration program is executed without any seed file, then the local /etc/hosts file is used as seed file for the tool.

The automatic configuration tool readhosts generates a HOSTS file in its current executing directory.

If the readhosts file is not able to find the MAC address of a network interface, then an entry NOT_FOUND is written to the HOSTS file instead of the MAC address of the network interface.

Both /usr/sap/tmp/R3net_conf and /usr/sap/tmp/HOSTS files are ASCII files, an administrator can manually edit these files with an ASCII editor such as vi.

If a MAC address of a host was written as NOT_FOUND , the administrator can manually use the commands ifconfig and lanscan to determine the missing MAC address of the network interface and replace the NOT_FOUND word with the actual MAC address.

 

See also:

Example: HOSTS File

readhosts