# IPv4/IPv6 Common Settings

### 1. Function Overview

This product is compatible with the following network environment settings that are common to IPv4 and IPv6, mainly for the purpose of maintenance (configuring the settings of the switch).

1. DNS client settings

2. Equal cost multipath settings

### 2. Definition of Terms Used

None

### 3. Function Details

#### 3.1. DNS client settings

This product supports DNS (Domain Name System) clients.
If an FQDN (Fully Qualified Domain Name) has been set for an NTP server or a syslog server, an inquiry is made to the DNS server to retrieve the IPv4/IPv6 address.

This product provides the following DNS client control functions.

- Set IP address of the DNS server

- Set default domain name

- Set search domain list

Inquiries to the DNS server are enabled by default, and the setting can be changed by using the dns-client enable/disable command.

##### 3.1.1. Set IP address of the DNS server

Up to three IP addresses can be set for the DNS server, using the methods shown below.

- Manual setting using the dns-client name-server command

  - This lets you specify the IPv4/IPv6 address.

- Automatic setting via DHCP

  - The highest default gateway value takes priority if there is more than one.

- Automatic setting via DHCPv6

  - If specifying multiple settings, the most recent is prioritized.

  - Link local addresses notified by DHCPv6 cannot be specified.

- If both DHCP and DHCPv6 are used, both settings will be overwritten when DNS server addresses are obtained.

This product always gives priority to the information that was set via commands.
Check the configured DNS servers by using the show dns-client command.

##### 3.1.2. Set default domain name

Only one default domain can be set using the methods shown below. The domain can be specified using up to 256 characters.

- Manual setting using the dns-client domain-name command

- Automatic setting via DHCP

  - The highest default gateway value takes priority if there is more than one.

Just as with DNS server IP addresses, this product prioritizes information specified with commands.
Check the default domain that was set by using the show dns-client command.
The use of a default domain is only allowed if there are no listings in the search domain list.

##### 3.1.3. Set search domain list

This product uses a search domain list to manage the domain names used when inquiring with the DNS.
Up to six domain names can be set on the search domain list using the method below.

- Manual setting using the dns-client domain-list command

- Automatic setting via DHCPv6

  - If specifying multiple settings, the most recent is prioritized.

Just as with DNS server IP addresses, this product prioritizes information specified with commands.
The search domain list that has been set can be checked using the show dns-client command.
The search domain list must be within 256 characters total for all domain names registered.

#### 3.2. Equal cost multipath settings

This product supports equal-cost multi-path settings using the following functions.

- IPv4 static routing

- IPv6 static routing

- RIPv1, RIPv2, RIPng (only on compatible models)

- OSPFv2, OSPFv3 (only on compatible models)

If multiple routes to the same destination are registered in the RIB, these multiple routes will be reflected in the FIB.
Up to eight routes leading to the same destination can be registered in the FIB. The default setting is four routes.
The number of equal-cost multi-paths that can be registered may be changed using the maximum-paths command.
The changes to the settings will not be reflected in actual operations until rebooting.

Use the port-channel load-balance command to configure the load balance rules for equal-cost multi-path destinations.
Caution must be used when changing the load balance rule settings using the port-channel load-balance command, as this has an impact on how link aggregation works.

### 4. Related Commands

Related commands are indicated below.
For details on the commands, refer to the Command Reference.

Function types | Operations | Operating commands
--- | --- | ---
DNS client settings | DNS client settings | dns-client enable/disable
Set DNS server address | dns-client name-server
Set default domain name | dns-client domain-name
Set search domain list | dns-client domain-list
Show DNS client settings | show dns-client
Equal cost multipath settings | Set the number of equal-cost multi-paths that can be registered | maximum-paths
Display the number of equal-cost multi-paths that can be registered | show ip route summary
show ipv6 route summary
Set load balance function rules | port-channel load-balance

### 5. Examples of Command Execution

#### 5.1. DNS client settings

Set DNS client settings for this product to prepare an environment for DNS queries.

- Specify 192.168.100.1 and 192.168.100.2 as the IP addresses of the servers for DNS queries.

- Specify example.com as the default domain used for DNS queries.

■ Setting Procedure

1. Enable the DNS query functionality.

       Yamaha(config)#dns-client enable

   - Since this is specified as the default value, we do not need to set this specifically.

2. Specify the DNS servers.

       Yamaha(config)#dns-client name-server 192.168.100.1
       Yamaha(config)#dns-client name-server 192.168.100.2

3. Set the default domain.

       Yamaha(config)#dns-client domain-name example.com

4. Check the DNS client information that was set.

       Yamaha#show dns-client

       DNS client is enabled
        Default domain  : example.com
        Domain list     :
        Name Servers    : 192.168.100.1 192.168.100.2

        * - Values assigned by DHCP or DHCPv6 Client.

#### 5.2. Equal-cost multi-paths

This changes the number of equal-cost multi-paths that can be registered to “5”.
Also, the source and destination IP addresses are used as load balance rules.

1. Set the number of equal-cost multi-paths that can be registered

       Yamaha(config)#maximum-paths 5
       % System Reboot is required for new Maximum-Path value to take effect.

   - A reboot is required to apply the settings.

2. Set the source and destination IP addresses as load balance rules.

       Yamaha(config)#port-channel load-balance src-dst-ip

3. Check the current number of equal-cost multi-paths that can be registered.

       Yamaha(config)#show ip route summary
       IP routing table name is Default-IP-Routing-Table(0)
       IP routing table maximum-paths   : 5
       Route Source    Networks
       connected       3
       rip             2
       Total           5

### 6. Points of Caution

None

### 7. Related Documentation

None

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