Using the /etc/hosts file to maintain host information

About the /etc/hosts file

Data ONTAP uses the /etc/hosts file to resolve host names to IP addresses, including host names used in any of the following files:

/etc/rc
/etc/syslog.conf
/etc/exports
/etc/netgroup
/etc/hosts.equiv

You must ensure that the /etc/hosts file is kept up-to-date. If you update the file, you do not need to reboot the filer--the changes to the file take effect immediately.

When Data ONTAP is first installed, the /etc/hosts file is automatically created with default entries for the following interfaces:

localhost
All interfaces on the filer
Note
The /etc/hosts file resolves the host names for the filer it is configured on. This file cannot be used by other systems for name resolution.

For more information on file format, see the NetApp hosts(5) manual page.

Ways to add entries to the /etc/hosts file

You can add IP address and hostname entries in the /etc/hosts file in the following two ways:

Locally
You might want to add entries to the local /etc/hosts file if the number of entries is small. You can do so
- At the command line
  See Editing the /etc/hosts file manually.
- Using FilerView
  See Editing the /etc/hosts file with FilerView.
Remotely using the NIS makefile master
If the number of entries is large and you have access to an NIS makefile master, you might want to use the makefile master to create the /etc/hosts file. This method prevents errors that could be introduced in the manual creation process. For details, see Creating /etc/hosts from the NIS master.

Note
Using NIS to distribute the /etc/hosts file is different from looking up host names on an NIS server. For more information about network lookups, see Using NIS to maintain host information.

Editing the /etc/hosts file manually

To edit the /etc/hosts file manually, complete the following steps.

Step	Action
1	From a workstation that has access to the filer's root volume, open the /etc/hosts file using a text editor.
2	Edit the file to your needs. The format of the file is as follows: IP address Host-name aliases
3	Save the file.

Step

Action

From a workstation that has access to the filer's root volume, open the /etc/hosts file using a text editor.

Edit the file to your needs. The format of the file is as follows:

IP address Host-name aliases

Save the file.

Example

The following shows how the entries might look in the /etc/hosts file on a filer:

192.16.3.145    toaster toaster-e0
192.16.4.155    toaster-e2
192.16.5.165    toaster-e4
192.16.6.175    toaster-e8

In the first line, the filer host name itself is used as an alias for the first network interface. That is, network traffic addressed to toaster will be received on the toaster-e0 interface.

Editing the /etc/hosts file with FilerView

To edit the /etc/hosts file with FilerView, complete the following steps.

Step	Action
1	In FilerView, click Network in the list on the left.
2	In the list under Network, click Manage Hosts File.
3	Click in the hosts window, then click Insert.
4	Complete the fields in the Create a New /etc/hosts Line window for each host you wish to add and click OK.
5	Click Apply in the Manage Hosts File window.

Creating /etc/hosts from the NIS master

To modify the makefile for the NIS master to create a hosts file and copy it to the /etc directory on the filer's default volume, complete the following steps.

Step	Action
1	On the NIS server, open the NIS makefile with an editor.
2	Locate the section for hosts.time.
3	Add the following lines at the end of the hosts.time section, replacing toaster 1, toaster2, and so on with names of your filers: @mntdir=/tmp/netapp_etc_mnt_$$$$;\ if [ ! -d $$mntdir ]; then rm -f $$mntdir; \ mkdir $$mntdir; fi;\ for filer in toaster1 toaster2 toaster3 ; do \ mount $$filer:/etc $$mntdir;\ mv $$mntdir/hosts $$mntdir/hosts.bak;\ cp /etc/hosts $$mntdir/hosts;\ umount $$mntdir;\ done;\ rmdir $$mntdir
4	Save the NIS makefile. The /etc/hosts file on the filer is updated whenever the NIS makefile is run.