The 3-DNS Controller must always be authoritative for your wide IP sub-domains, regardless of which server is the authoritative DNS for the network. However, we strongly recommend that you set up the 3-DNS Controller as authoritative for your domain.

One major benefit of setting up the 3-DNS Controller to be authoritative for your domain is that you can easily manage DNS zone files using NameSurfer, a browser-based, third-party application included on the 3-DNS Controller. With NameSurfer, you can also easily transfer your existing zone files to the 3-DNS Controller after the initial installation.

When you define wide IPs in the Configuration utility, the NameSurfer application automatically makes the appropriate additions to the zone files, and broadcasts the new zone files to the other DNS servers in your network. If you configure wide IPs manually, however, you need to make the corresponding zone file changes manually.

If you use the advanced synchronization features of the 3-DNS Controller, we strongly recommend that you configure each 3-DNS Controller to run as authoritative for the domain. This type of configuration offers the following advantages:

Replacing your DNS servers with 3-DNS Controllers

Figure 2.1 shows an implementation where both 3-DNS Controllers in the network are authoritative for the domain, domain.com.

Figure 2.1 Using 3-DNS Controllers as authoritative DNS servers

Converting existing BIND files during an initial installation

After you initially install the 3-DNS Controller, you need to transfer existing BIND files, and then convert them to the NameSurfer format.

The first option for importing your existing BIND files is to transfer your zone files from your current name server to NameSurfer. After configuring NameSurfer during the First-Time Boot utility and connecting to the Configuration utility, use the Copy from other name server option in the NameSurfer UI. For more information, refer to the NameSurfer documentation available from the splash screen in the Configuration utility.

The second option for converting your existing BIND files is to skip the NameSurfer configuration when you run the First-Time Boot utility. You transfer the zone files and named.conf file after the system has rebooted, and then run the config_namesurfer script that configures, converts, and starts the NameSurfer application.

Warning: We recommend that you transfer your existing zone files using NameSurfer during the First-Time Boot utility. If you choose to transfer your existing zone files using the config_namesurfer script, please consult with your F5 Networks technical resource first. You can also find assistance on AskF5, the F5 Networks knowledge base.

Running 3-DNS Controllers as authoritative for sub-domains only

At a minimum, all 3-DNS Controllers must be authoritative for the zones associated with wide IP definitions. When you set up a configuration where the 3-DNS Controllers are authoritative for only those sub-domains, you need to make a few changes to the zone files on the DNS server that is authoritative for the domain, after you configure the 3-DNS Controller.

Figure 2.2 shows an example where both 3-DNS Controllers are authoritative for the wide IP sub-domain, wip.domain.com, and a generic name server in the Tokyo data center is authoritative for the domain, domain.com.

Figure 2.2 Using 3-DNS Controllers as authoritative DNS servers for sub-domains

Note that you should still set NameSurfer to be authoritative during the First-Time Boot utility for initial installations, or during the NameSurfer configuration script for upgrade installations. Remember that NameSurfer is authoritative for the zone files on the 3-DNS Controller, but in this configuration, the zone files contain only those records associated with wide IPs configured on the 3-DNS Controller. When you configure wide IPs in the Configuration utility, the NameSurfer application automatically updates the corresponding sub-domain zones and broadcasts them to the other DNS servers in the network. For configurations where synchronization is enabled, changes to any NameSurfer files are automatically updated to the other 3-DNS Controllers.

Setting up a basic configuration

The second phase of installing 3-DNS Controllers is to define the network setup. Each 3-DNS Controller in the network setup must have information regarding which data center stores specific servers, and with which other 3-DNS Controllers it can share configuration and load balancing information. A basic network setup includes data centers, servers, and one sync group. Once you have the basic network components configured on your 3-DNS Controller, you can set up the wide IPs you need for managing your load balancing. We recommend that you review the load balancing scenarios in the remaining chapters of this guide before you configure the wide IPs.

The following sections describe the various elements of a basic network:

• Data centers
  Data centers are the top level of your network setup. We recommend that you configure one data center for each physical location in your global network. The data center element of your configuration defines the servers (3-DNS Controllers, BIG-IP Controllers, EDGE-FX Caches, and hosts) that reside at that location.
  
  A data center can contain any type of server. For example, in Figure 2.3 , the Tokyo data center contains a 3-DNS Controller and a host, while the New York and Los Angeles data centers contain 3-DNS Controllers and BIG-IP Controllers.
  
  For information about configuring data centers, see Setting up a data center, on page 2-16 .
• Servers
  The servers that you define in the network setup include 3-DNS Controllers, BIG-IP Controllers, EDGE-FX Caches, and host machines. You define the 3-DNS Controllers that manage the BIG-IP Controllers, EDGE-FX Caches, and hosts, and you also define the virtual servers that are managed by the servers. Virtual servers are the ultimate destination for connection requests.
  
  For information about configuring servers, see Setting up servers, on page 2-19 .
• Sync groups
  Sync groups contain only 3-DNS Controllers. When setting up a sync group, you define which 3-DNS Controllers have the same configuration. In most cases, you should define all 3-DNS Controllers as part of the same sync group.
  
  For information about configuring sync groups, see Setting up sync groups, on page 2-35 .
• Wide IPs
  After you define virtual servers for your BIG-IP Controllers and hosts, you need to specify how connections are distributed among the virtual servers by defining wide IPs. A wide IP maps a domain name to a pool of virtual servers, and it specifies the load balancing modes that the 3-DNS Controller uses to choose a virtual server from the pool.
  
  When an LDNS requests a connection to a specific domain name, the wide IP definition specifies which virtual servers are eligible to answer the request, and which load balancing modes to use in choosing a virtual server to resolve the request.
  
  For information about configuring wide IPs and choosing load balancing modes, please refer to Chapter 5, Load Balancing, in the 3-DNS Controller Reference Guide.
• Global variables
  You can configure global variables that apply to all servers and wide IPs in your network. However, the default values of the global variables work well for most situations, so configuring global variables is optional.
  
  For information about configuring global variables, see Configuring global variables .

Setting up a data center

The first step in configuring your 3-DNS Controller network is to create data centers. A data center defines the group of 3-DNS Controllers, BIG-IP Controllers, EDGE-FX Caches, and hosts that reside in a single physical location. Figure 2.3 shows an example of a data center.

The advantage of grouping all machines from a single physical location into one data center in the configuration is to allow path information collected by one machine to be shared with all other machines in the data center. The 3-DNS Controller uses the big3d agent to collect path and metrics information about the other machines, and their virtual servers, in the data center. The 3-DNS Controller then applies path metrics results to all the virtual servers in the data center when making load balancing decisions.

Figure 2.3 Example data center setup

To configure a data center using the Configuration utility

1. In the navigation pane, click Data Centers.
2. On the toolbar, click Add Data Center.
   The Add New Data Center screen opens.
3. Add the new data center settings. For help on defining data centers, click Help on the toolbar.
   The data center is added to your configuration.
4. Repeat this process for each data center in your network.

   When you add servers to the network setup, you assign the servers to the appropriate data centers.

To configure a data center using the command line utility

1. At the command prompt, type 3dnsmaint to open the 3-DNS Maintenance menu.
2. Select Edit 3-DNS Configuration to open the wideip.conf file.
   The editor variable determines whether this command starts vi or pico.
3. Locate or add the datacenter statement.

   The datacenter statement should be the second statement in the file, after the globals statement and before server statements.

4. In the first line of the datacenter statement, type a name for the data center and enclose the name in quotation marks, as shown in Figure 2.4 .
5. Type the server type and IP address for each server that is part of the specified data center.

   Figure 2.4 shows the correct syntax for the datacenter statement.

   Figure 2.4 Syntax for the datacenter statement

    datacenter {    
        name <"data center name">    
        [ location <"location info"> ]    
        [ contact <"contact info"> ]    
        [ 3dns <IP address> ]    
        [ bigip <IP address> ]    
        [ edge_fx <IP address> ]    
        [ host <IP address> ]    
      }    

   Repeat the preceding procedure until you have added a separate datacenter statement for each data center in your network.

   Figure 2.5 shows a sample datacenter statement.

   Figure 2.5 Sample data center definition

    datacenter {    
        name "New York"    
        location "NYC"    
        contact "3DNS_Admin"    
        3dns 192.168.101.2    
        bigip 192.168.101.40    
        host 192.168.105.40    
      }     

Setting up servers

There are four types of servers: 3-DNS Controllers, BIG-IP Controllers, EDGE-FX Caches, and hosts. At the minimum, your network includes one 3-DNS Controller, and at least one server (BIG-IP Controller, EDGE-FX Cache, or host) that it manages.

This section describes how to set up each 3-DNS Controller, BIG-IP Controller, EDGE-FX Cache, and host machine that make up your network. The setup procedures here assume that the BIG-IP Controllers, EDGE-FX Caches, and hosts are up and running, and that they already have virtual servers defined. Note that 3-DNS Controllers do not manage virtual servers.

Defining 3-DNS Controller servers

The purpose of defining a 3-DNS Controller server is to establish in which data center the 3-DNS Controller resides and, if necessary, to change big3d agent settings. In setting up a 3-DNS Controller server, you also make that 3-DNS Controller available so you can add it to a sync group.

Note: Please review Chapter 5, Adding 3-DNS Controllers to the Network , if you are configuring more than one 3-DNS Controller in your network.

To define a 3-DNS Controller server using the Configuration utility

1. In the navigation pane, expand the Servers item, then click 3-DNS Controllers.
2. On the toolbar, click Add 3-DNS Controller.
   The Add New 3-DNS Controller screen opens.
3. Add the new 3-DNS Controller settings. For help on defining 3-DNS Controllers, click Help on the toolbar.

The 3-DNS Controller is added to your configuration. Repeat this procedure for each 3-DNS Controller you need to add.

To define a 3-DNS Controller server using the command line utility

1. At the command prompt, type 3dnsmaint to open the 3-DNS Maintenance menu.
2. On the 3-DNS Maintenance menu, select Edit 3-DNS Configuration to open the wideip.conf file.
3. Use the syntax shown in Figure 2.6 to define a 3-DNS Controller.

   All server statements should appear after the sync_group statement and before wideip statements.

   Figure 2.6 Syntax for defining a 3-DNS Controller server

    server {    
        type 3dns    
        address <IP address>    
        name <"3dns_name">    
        iquery_protocol [ udp | tcp ]    
        [ remote {    
          secure <yes | no>    
          user <"user name">    
          } ]    
        [ interface {    
          address <NIC IP address>    
          address <NIC IP address>    
          } ]    
        [ factories {    
          prober <number>    
          discovery <number>    
          snmp <number>    
          hops <number>    
          } ]    
        [ prober <IP address> ]    
        probe_protocol < icmp | udp | tcp | dns_rev | dns_dot>    
        port <port to probe>    
      }    

   Figure 2.7 shows a sample server statement that defines a 3-DNS Controller.

   Figure 2.7 Sample 3-DNS Controller server definition

    // New York    
      server {    
         type 3dns    
         address 192.168.101.2    
         name "3dns-newyork"    
         iquery_protocol  udp     
         remote {    
            secure yes    
            user "root"    
         }    
         prober 192.168.101.40     
         probe_protocol dns_rev    
         port 53    
      }     

Defining BIG-IP Controller servers

Before you define BIG-IP Controller servers, you should have the following information:

• The IP address and service name or port number of each virtual server to be managed by the BIG-IP Controller
• The IP address of the server itself

To define a BIG-IP Controller server using the Configuration utility

1. In the navigation pane, expand the Servers item, and then click BIG-IP Controllers.
2. On the toolbar, click Add BIG-IP Controller.
   The Add New BIG-IP Controller screen opens.
3. Add the new BIG-IP Controller settings. (For help on defining BIG-IP Controllers, click Help on the toolbar.)
   The BIG-IP Controller and specified virtual server are added to your configuration.

To add more virtual servers using the Configuration utility

1. In the navigation pane, expand the Servers item, and then click BIG-IP Controllers.
2. In the table, find the BIG-IP Controller that you just added.
3. Click the entry in its BIG-IP Virtual Servers column.
4. On the toolbar, click Add Virtual Server.
   The Add Virtual Server to BIG-IP screen opens.
5. Add the new virtual server settings. For help on adding virtual servers, click Help on the toolbar.

Repeat this process for each virtual server you want to add to this BIG-IP Controller.

To define a BIG-IP Controller server using the command line utility

1. At the command prompt, type 3dnsmaint to open the 3-DNS Maintenance menu.
2. On the 3-DNS Maintenance menu, select Edit 3-DNS Configuration to open the wideip.conf file.
3. Use the syntax shown in Figure 2.8 to define a BIG-IP Controller.

   All server statements should appear after the sync_group statement and before wideip statements.

   If you need to allow iQuery packets to pass through firewalls, include the translate keyword in the server statement that defines the BIG-IP Controller. When you include the translate keyword, the iQuery utility includes translated IP addresses in the packets sent to the specific BIG-IP Controller. For more information on configuring the big3d agent and iQuery, see Chapter 3, big3d Agent, of the 3-DNS Controller Reference Guide.

   Figure 2.8 Syntax for defining a BIG-IP Controller server

    server {    
        type bigip    
        address <IP address>    
        name <"bigip_name">    
        iquery_protocol [ udp | tcp ]    
        limit {    
        [ kbytes_per_second <number>    
          packets_per_second <number>    
          disk_avail <number>    
          cpu_usage <number>    
          memory_avail <number>    
          current_connections <number> ]    
         }    
        [ remote {    
          secure <yes | no>    
          user <"user name">    
          } ]    
        [ interface {    
          address <NIC IP address>    
          address <NIC IP address>    
          } ]    
        [ factories {    
          prober <number>    
          discovery <number>    
          snmp <number>    
          hops <number>    
          } ]    
             
        vs {     
          address <virtual server IP address>     
          port <port number> | service <"service name">    
          [ translate {    
              address <IP address>    
              port <port number>|service <"service name">    
            } ]    
         }    
      }     

   Figure 2.9 shows a sample server statement that defines a BIG-IP Controller.

   Figure 2.9 Sample BIG-IP Controller server definition

    server {     
         type            bigip    
         address         192.168.101.40    
         name            "bigip-newyork"    
         iquery_protocol  udp     
         remote {    
            secure       yes    
            user         "administrator"    
         }    
         # Tell 3-DNS about the 2 interfaces on a BIG-IP HA    
         interface {    
            address      192.168.101.41    
            address      192.168.101.42    
         }    
         # Change the number of factories doing the work at big3d    
         factories {    
            prober     6    
            discovery  1    
            snmp       1    
            hops       2    
         }    
         vs {    
            address         192.168.101.50    
            service         "http"    
            translate {    
               address      10.0.0.50    
               port         80    
            }    
         }    
         vs {    
            address         192.168.101.50:25 // smtp    
            translate {    
               address      10.0.0.50:25    
            }    
         }    
      }    

Defining EDGE-FX Caches

Before you define EDGE-FX Cache servers, you should have the following information:

• The IP address and service name or port number of each virtual server to be managed by the EDGE-FX Cache
• The IP address of the cache itself

To define an EDGE-FX Cache server using the Configuration utility

1. In the navigation pane, expand the Servers item, then click EDGE-FX Caches.
2. On the toolbar, click Add EDGE-FX Cache.
   The Add New EDGE-FX Cache screen opens.
3. Add the new EDGE-FX Cache settings. (For help on defining an EDGE-FX Cache, click Help on the toolbar.)
   The EDGE-FX Cache and specified virtual server are added to your configuration.

To add more virtual servers using the Configuration utility

1. In the navigation pane, click Servers, then click EDGE-FX Caches.
2. In the table, find the EDGE-FX Cache that you just added.
3. Click the entry in its EDGE-FX Virtual Servers column.
4. On the toolbar, click Add Virtual Server.
   The Add Virtual Server to EDGE-FX screen opens.
5. Add the new virtual server settings. For help on adding virtual servers, click Help on the toolbar.
   
   Repeat this process for each virtual server you want to add to this EDGE-FX Cache.

To define an EDGE-FX Cache server using the command line utility

1. At the command prompt, type 3dnsmaint to open the 3-DNS Maintenance menu.
2. On the 3-DNS Maintenance menu, select Edit 3-DNS Configuration to open the wideip.conf file.
3. Use the syntax shown in Figure 2.10 to define a EDGE-FX Cache.

   Figure 2.10 Syntax for defining an EDGE-FX Cache server

    server {    
      type edge_fx    
      address <IP address>    
      name <"edge_name">    
      iquery_protocol [ udp | tcp ]    
      limit {    
      [ kbytes_per_sec <number>    
        pkts_per_sec   <number>    
        current_conns  <number>    
        cpu_usage      <number>    
        mem_avail      <number>    
        disk_avail     <number> ]    
      }    
      [ remote {    
      secure <yes | no>    
      user <"user name">    
      }]    
      [ interface {    
      address <NIC IP address>    
      address <NIC IP address>    
      }]    
      [ factories {    
      prober <number>    
      discovery <number>    
      snmp <number>    
      hops <number>    
      }]    
      vs {    
      address <virtual server IP address>    
      port <port number> | service <"service name">    
      }    
      }     

   In the wideip.conf file, all server statements should appear after the sync_group statement and before wideip statements.

   If you need to allow iQuery packets to pass through firewalls, include the translate keyword in the server statement that defines the EDGE-FX Cache. When you include the translate keyword, the iQuery utility includes translated IP addresses in the packets sent to the specific EDGE-FX Cache. For more information on configuring the big3d agent and iQuery, see Chapter 3, big3d Agent, of the 3-DNS Controller Reference Guide.

   Figure 2.11 shows a sample server statement that defines an EDGE-FX Cache.

   Figure 2.11 Sample EDGE-FX Cache server definition

    server { // datacenter=East Coast, #VS=1    
       type edge_fx    
            address 192.168.10.150    
            name "edge_east1"    
            limit { /* none */ }    
            iquery_protocol udp    
            remote { secure yes     
                     user "root" }    
            factories {     
               snmp 1 }    
            vs {    
               address 10.10.10.10:80 // http    
               limit { /* none */ }    
               probe_protocol tcp    
          }    
       }      

Defining host servers

A host is an individual network server or server array controller other than the BIG-IP Controller or EDGE-FX Cache. Before configuring a host, you should have the following information:

• Address information
  The IP address and service name or port number of each virtual server to be managed by the host.
• SNMP information for host probing
  To implement host probing and to collect performance metrics, you must specify SNMP agent settings after you define the host server. The settings you specify include the type and version of SNMP agent that runs on the host, the community string, and the number of communication attempts that you want the big3d agent to make while gathering host metrics. SNMP agent settings for hosts are described in Configuring host SNMP settings .

  Note: To fully configure host probing, you must configure the SNMP agent settings in the host definition as previously described, and you must also set up the big3d agents to run SNMP factories, and configure the SNMP agents on the hosts themselves. For details, please refer to Chapter 3, big3d Agent, and Chapter 10, SNMP, in the 3-DNS Controller Reference Guide.

To define a host server using the Configuration utility

1. In the navigation pane, expand the Servers item, and then click Host Servers.
2. On the toolbar, click Add Host Server.
   The Add New Host Server screen opens
3. Add the new host server settings. For help on adding host servers, click Help on the toolbar.
   The host and the specified virtual server are added to your configuration.

To add more virtual servers using the Configuration utility

1. In the navigation pane, click Host Servers.
2. In the table, find the host that you just added, and click the entry in its Host Virtual Servers column.
3. On the toolbar, click Add Host Virtual Server.
   The Add Virtual Server to Host screen opens.
4. Add the new virtual server settings. For help on adding virtual servers, click Help on the toolbar.
   
   Repeat this process for each virtual server you want to add to this host.

To define a host server using the command line utility

1. At the command prompt, type 3dnsmaint to open the 3-DNS Maintenance menu.
2. On the 3-DNS Maintenance menu, select Edit 3-DNS Configuration to open the wideip.conf file.
3. Use the syntax shown in Figure 2.12 to define a host.

   All server statements should appear after the sync_group statement and before wideip statements.

   Figure 2.12 Syntax for defining a host server

    server {    
        type host    
        address <IP address>    
        name <"host_name">    
        [ prober <ip_address> ]    
        probe_protocol <tcp | icmp | udp | dns_rev | dns_dot>    
        port <port number> | service <"service name">    
        [ snmp {    
          agent <generic | ucd | solstice | ntserv | ciscoldv2 | ciscoldv3 | arrowpoint | foundry | alteon | cacheflow | win2kserv>    
          port <port number>    
          community <"community string">    
          timeout <seconds>    
          retries <number>    
          version <SNMP version>    
          } ]    
        vs {     
          address <virtual server IP address>     
          port <port number> | service <"service name">    
          [ probe_protocol <tcp | icmp | udp | dns_rev | dns_dot> ]    
        }    
      }    

   Figure 2.13 shows a sample server statement that defines a host.

   Figure 2.13 Sample host server definition

    server {     
         type            host    
         address         192.168.104.40    
         name            "host-tokyo"    
         prober          192.168.101.40    
         probe_protocol  icmp    
         port            53    
         snmp {    
            agent        ucd    
            community    "public"    
            version      1    
         }    
         vs {    
            address         192.168.104.50:25     
         }    
         vs {    
            address         192.168.104.50:80    
         }    
      }     

Configuring host SNMP settings

After defining a host server, you need to configure its SNMP settings if you want to use SNMP host probing. Remember that you must first set up at least one SNMP probing factory on any 3-DNS Controller or BIG-IP Controller that runs the big3d agent.

The SNMP prober collects some or all of the following information from hosts.

• Memory utilization
• CPU utilization
• Disk space utilization
• Packet rate (packets per second
• Throughput rate (kilobytes per second)
• Current connections

The 3-DNS Controller uses this performance information for advanced load balancing modes such as Packet Rate, Quality of Service, and Kilobytes/Second.

The 3-DNS Controller supports the following host SNMP agents:

Viewing host performance metrics

The Configuration utility displays the host metrics in the Host statistics screen. The 3-DNS Controller bases the advanced load balancing decisions on packet rate, kilobytes per second, and current connections metrics, but the Host screen displays the other metrics as well, for information purposes.

Reviewing SNMP configuration issues

The SNMP probing feature requires that each host run an SNMP agent, and that there is open network communication between the hosts and the big3d agents in the data centers. Certain firewall configurations block SNMP communications, and you may need to verify that the firewalls in your network allow SNMP traffic to pass through. For information on configuring the big3d agent and working with firewalls, see Chapter 3, big3d Agent, in the 3-DNS Controller Reference Guide.

In addition to properly configuring the SNMP agents on the hosts themselves, you need to specify SNMP host probing settings in two places in the 3-DNS Controller configuration. First, when you define a BIG-IP Controller or 3-DNS Controller server, you set the big3d agent to run at least one SNMP factory. Second, when you define the host servers, you configure specific SNMP agent settings for each host. For example, you need to specify the type of agent running on the host as well as the community string that allows access to the SNMP agent. For more information on configuring SNMP agents, please review Chapter 10, SNMP, in the 3-DNS Controller Reference Guide.

The SNMP chapter also includes some useful tips on configuring the different SNMP agents on the hosts themselves. We recommend that you use the information in conjunction with the documentation originally provided with the SNMP agent.

Setting up sync groups

A sync group defines a group of 3-DNS Controllers that synchronize their configuration settings and metrics data. A sync group contains a principal controller and one or more receiver controllers. The principal controller is the 3-DNS Controller from which the receiver controllers obtain their metrics and server statistics information. You configure a sync group from the principal 3-DNS Controller. First list the IP address of the principal itself. Then list the receiver 3-DNS Controllers in the order that they should become principals if previously listed 3-DNS Controllers fail.

Each 3-DNS Controller in your network must be included in a sync group. There may be cases where you do not want a 3-DNS Controller to share its configuration with other controllers. In this case, you can create a separate sync group for each 3-DNS Controller. Each sync group contains only its own name or IP address.

Figure 2.14 Sample non-syncing sync groups statements

 sync_group {    
     name "sync-ny"    
     3dns 192.168.101.2    // New York    
   }    
       
   sync_group {    
     name "sync-la"    
     3dns 192.168.102.2    // Los Angeles    
   }    

Note: To implement such a configuration, you must modify each 3-DNS Controller's wideip.conf file; the Configuration utility does not support this function.

To define a sync group using the Configuration utility

1. In the navigation pane, click 3-DNS Sync.
   The System - Add a New Sync Group screen opens.
2. In the New Sync Group Name box, type the name of the new sync group and click Add.
   The Add a 3-DNS to a Sync Group screen opens.
3. From the list of 3-DNS Controllers, first select the 3-DNS Controller that you want to be the principal controller. Then check the box next to each 3-DNS Controller that you want to add to the sync group.
4. Click Add.

To define a sync group using the command line utility

1. At the command prompt, type 3dnsmaint to open the 3-DNS Maintenance menu.
2. On the 3-DNS Maintenance menu, select Edit 3-DNS Configuration to open the wideip.conf file.
3. Use the syntax shown in Figure 2.15 to define sync groups.

   The sync_group statement should appear after the datacenter statement and before server statements.

   Figure 2.15 Syntax for setting up a sync group

    sync_group {    
        name "<name>"    
        3dns <ip_address | "domain_name">    
        [ 3dns <ip_address | "domain_name"> ] ...    
      }     

   Figure 2.16 shows a sample sync_group statement.

   Figure 2.16 Sample sync group definition

    sync_group {    
        name "default"    
        3dns 192.168.101.2    // New York    
        3dns 192.168.102.2    // Los Angeles    
      }    

Setting the time tolerance value

The time tolerance value is a global variable that defines the number of seconds that one 3-DNS Controller's time setting is allowed to be out of sync with another 3-DNS Controller's time setting. We recommend that you leave the time tolerance variable at the default setting of 10.

To check the value for the time tolerance setting using the Configuration utility

1. In the navigation pane, click System.
   The System - General screen opens.
2. On the toolbar, click Timers and Task Intervals.
3. Note the value in the 3-DNS Sync Time Tolerance box, and change it if necessary.
4. If you change this setting, click Update to save it. For more information about the settings on this screen, click Help on the toolbar.

To check the value for the time tolerance setting in the configuration file

1. At the command prompt, type 3dnsmaint to open the 3-DNS Maintenance menu.
2. On the 3-DNS Maintenance menu, select Edit 3-DNS Configuration to open the wideip.conf file.
3. Search for time_tolerance. If the time_tolerance sub-statement is not in the configuration file, the default (10) is used.

Configuring global variables

The default values for global parameters are sufficient for most load balancing situations. However, we recommend that you specifically enable encryption for crypto 3-DNS Controllers.

To configure global parameters using the Configuration utility

1. In the navigation pane, click System.
   The System - General screen opens. Note that global parameters are grouped into several categories on this screen. Each category has its own toolbar item, and online help is available for each parameter.
2. Make general global changes at the System - General screen or, to make changes to global parameters in other categories, click the appropriate toolbar item.
3. Add the new global settings. For help on configuring the global settings, click Help on the toolbar.

The new global parameters are added to your configuration.

To configure global parameters using the command line utility

1. At the command prompt, type 3dnsmaint to open the 3-DNS Maintenance menu.
2. On the 3-DNS Maintenance menu, select Edit 3-DNS Configuration to open the wideip.conf file.
3. Locate or add the globals statement. The globals statement should be at the top of the file.
4. Under the globals statement, type the appropriate sub-statement and value.

   For example, to enable encryption for iQuery transactions (which is recommended), change the encryption parameter to yes (the default setting is no). If you want to use a non-default name for the encryption key file, type it on the next line.

   Figure 2.17 shows the correct syntax for enabling encryption.

   Figure 2.17 Syntax for enabling encryption

    globals {    
         encryption yes    
         encryption_key_file "/etc/F5key.dat"    
      }     

For descriptions of all global parameters, refer to Chapter 13, wideip.conf Configuration, in the 3-DNS Controller Reference Guide.