Configuring DNS Servers

This chapter includes the following sections:

DNS Servers in Cisco UCS

You need to specify an external DNS server for each Cisco UCS domain to use if the system requires name resolution of hostnames. For example, you cannot use a name such as www.cisco.com when you are configuring a setting on a fabric interconnect if you do not configure a DNS server. You would need to use the IP address of the server, which can be either an IPv4 or an IPv6 address. You can configure up to four DNS servers for each Cisco UCS domain.


Note

When you configure multiple DNS servers, the system searches for the servers only in any random order. If a local management command requires DNS server lookup, it can only search for three DNS servers in random order.

Configuring a DNS Server

Procedure
     Command or ActionPurpose
    Step 1UCS-A# scope system  

    Enters system mode.

     
    Step 2UCS-A /system # scope services  

    Enters system services mode.

     
    Step 3UCS-A /system/services # create dns {ip-addr ip6-addr}  

    Configures the system to use the DNS server with the specified IPv4 or IPv6 address.

     
    Step 4UCS-A /system/services # commit-buffer  

    Commits the transaction to the system configuration.

     

    The following example configures a DNS server with the IPv4 address 192.168.200.105 and commits the transaction:

    UCS-A# scope system
UCS-A /system # scope services
UCS-A /system/services # create dns 192.168.200.105
UCS-A /system/services* # commit-buffer
UCS-A /system/services #

    The following example configures a DNS server with the IPv6 address 2001:db8::22:F376:FF3B:AB3F and commits the transaction:

    UCS-A# scope system
UCS-A /system # scope services
UCS-A /system/services # create dns 2001:db8::22:F376:FF3B:AB3F
UCS-A /system/services* # commit-buffer
UCS-A /system/services #

    Deleting a DNS Server

    Procedure
       Command or ActionPurpose
      Step 1UCS-A# scope system  

      Enters system mode.

       
      Step 2UCS-A /system # scope services  

      Enters system services mode.

       
      Step 3UCS-A /system/services # delete dns ip-addr  

      Deletes the NTP server with the specified IP address.

       
      Step 4UCS-A /system/services # commit-buffer  

      Commits the transaction to the system configuration.

       

      The following example deletes the DNS server with the IP address 192.168.200.105 and commits the transaction: 

      UCS-A# scope system
UCS-A /system # scope services
UCS-A /system/services # delete dns 192.168.200.105
UCS-A /system/services* # commit-buffer
UCS-A /system/services #