Manual Chapter : 3-DNS Administrator Guide, v1.0.6: Additional System and Network Configuration

Applies To:

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3-DNS Controller versions 1.x - 4.x

  • 1.0.6
Manual Chapter


Additional System and Network Configuration

Changing passwords for the 3DNS Controller

The First-Time Boot utility prompts you to define a password that allows remote access to the 3DNS Controller, and also prompts you to define a password for the 3DNS Web server. You can change these passwords at any time.

Changing the 3DNS Controller password

  1. At the 3DNS Controller command line prompt, log in as root and use the passwd command.
  2. At the password prompt, enter the password you want to use for the 3DNS Controller and press Return.
  3. To confirm the password, retype it and press Return.

Changing passwords and adding new user IDs

You can create new users for the 3DNS Web server, change a password for an existing user, or recreate the password file altogether, without actually going through the 3DNS Web server configuration process:

  1. Start the 3DNS menu by entering the following command from /usr/contrib/bin:


  1. From the 3DNS Maintenance Menu, select Add 3DNS Administration Password.

    This starts the 3dns_web_passwd script, which lets you provide access to the 3DNS Web Administration site for selected users only, and assigns passwords for those users. If you don't use this script, all users have access to the Web Administration site.

Configuring Sendmail

You can configure the 3DNS Controller to allow electronic mail to be sent from the system. This configuration must be completed if the 3DNS Controller is to send electronic mail to the administration workstation or to an alphanumeric pager. The 3DNS platform includes an example configuration file that is suitable for most sites. Before you use this configuration file, however, you do have to customize it for your network environment.

Customizing the /etc/sendmail file

When you customize this file, you enter the name of the mail relay server.

Finding the mail relay in your network

  1. From a machine capable of name resolution, type the following on the command line:

3dns: /etc# nslookup

  1. The command returns a default server name and corresponding IP address:
    Default Server: <server name>
    Address: <server
  2. Next, query for the mail relay server for your domain using the following command:

set q=mx
<domain name>

The information returned includes the name of the mail exchanger.

Setting up Sendmail

  1. Copy /etc/ to /etc/
  2. Edit /etc/ and set the DS variable to the name of the mail exchange server.
  3. Open the /etc/crontab file, and change the last line of the file to read:

0,15,30,45 * * * * root /usr/sbin/sendmail -q > /dev/null 2>&1

Including this line in the /etc/crontab file sets Sendmail to flush the outgoing message queue for any email that could not be delivered immediately. Because the 3DNS Controller does not accept email from external sources, there is no need to run the Sendmail daemon. Queue flushes are issued via crontab.

  1. Save and close the /etc/crontab file.
  2. Open the /etc/aliases file.
  3. In the /etc/aliases file, create an entry for root to point to an administrator at your site. For example:


Because the 3DNS Controller does not accept local email, bounces or undelivered messages go unnoticed. This requires that the administrator is notified when a message is bounced or undelivered.

  1. Save and close the /etc/aliases file.
  2. Run the newaliases command to generate the new aliases database using the information you just added.
  3. Reboot the 3DNS Controller.

Enabling dynamic routing

The 3DNS platform includes the GateD daemon, which is disabled by default. To enable the 3DNS Controller to accept dynamic routing updates from your routers, you must first create the appropriate configuration file, /etc/gated.conf.

Enabling the GateD daemon

You enable the GateD daemon on the 3DNS Controller by typing the following at the command line prompt:

3dns# gated

Editing the /etc/netstart file

Next, you need to edit the /etc/netstart file and change the definition of the gated variable as shown below:


The 3DNS Controller is now configured to accept dynamic route updates from your router.

Note: Certain network environments may require that you modify the routing tables or your router. If you have communication problems between your router and the 3DNS Controller, please contact Technical Support at F5 Networks, Inc.