Manual Chapter : Configuring a TTL in a Return Code On Failure

Applies To:

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BIG-IP DNS

  • 14.0.1, 14.0.0

BIG-IP LTM

  • 14.0.1, 14.0.0
Manual Chapter

Configuring a TTL in a Return Code On Failure

Overview: Configuring a SOA Negative Caching TTL in a Return Code on Failure

You can configure BIG-IP® DNS to return a start of authority (SOA) Negative Caching time-to-live (TTL). With this configuration, local DNS servers can cache a negative response. Negative caching reduces both the response time for negative DNS responses and the number of messages that must be sent between resolvers and local DNS servers.

About SOA records and negative caching

A start of authority (SOA) record contains a TTL by which a local DNS server can be configured to cache a Return Code On Failure to a query

Task summary for configuring TTL in return code on failure

You can configure DNS to provide a negative caching TTL for a domain name by performing these specific tasks.

Creating a pool with an applicable pool type

Ensure that at least one virtual server or wide IP exists in the configuration before you start to create a load balancing pool.
Create a pool in order to configure the BIG-IP system to load balance global traffic.

Creating a pool with pool type A or AAAA

Create an A or AAAA pool type in order to configure the BIG-IP system to load balance global traffic.
  1. On the Main tab, click
    DNS
    GSLB
    Pools
    .
    The Pool List screen opens.
  2. Click
    Create
    .
    The New Pool screen opens.
  3. In the General Properties area, in the
    Name
    field, type a name for the pool.
    Names must begin with a letter, and can contain only letters, numbers, and the underscore (_) character.
    The pool name is limited to 63 characters.
  4. From the
    Type
    list, depending on the type of the system (IPv4 or IPv6), select either an
    A
    or
    AAAA
    pool type.
  5. In the Configuration area, for the
    Health Monitors
    setting, in the
    Available
    list, select a monitor type, and move the monitor to the
    Selected
    list.
    Hold the Shift or Ctrl key to select more than one monitor at a time.
  6. In the Members area, for the
    Load Balancing Method
    setting, from the
    Preferred List
    , select
    Round Robin
    .
    When deploying this implementation in a lab environment, to determine whether the BIG-IP system returns the DNS response that you expect, try selecting the
    Global Availability
    method and disabling the first pool member in the list.
  7. From the
    Alternate
    and
    Fallback
    lists, select a static load balancing method, based on your network environment. Ensure that you select a load balancing method that does not take current server performance or connection load into account.
  8. In the Members area, for the
    Member List
    setting, add virtual servers as members of this load balancing pool.
    The system evaluates the virtual servers (pool members) in the order in which they are listed. A virtual server can belong to more than one pool.
    1. Select a virtual server from the
      Virtual Server
      list.
    2. Click
      Add
      .
  9. Click
    Finished
    .

Creating a pool with pool type NAPTR

Create an NAPTR pool type in order to configure the BIG-IP system to load balance global traffic.
  1. On the Main tab, click
    DNS
    GSLB
    Pools
    .
    The Pool List screen opens.
  2. Click
    Create
    .
    The New Pool screen opens.
  3. In the General Properties area, in the
    Name
    field, type a name for the pool.
    Names must begin with a letter, and can contain only letters, numbers, and the underscore (_) character.
    The pool name is limited to 63 characters.
  4. From the
    Type
    list, select the
    NAPTR
    type.
  5. In the Members area, for the
    Load Balancing Method
    setting, from the
    Preferred List
    , select
    Round Robin
    .
    When deploying this implementation in a lab environment, to determine whether the BIG-IP system returns the DNS response that you expect, try selecting the
    Global Availability
    method and disabling the first pool member in the list.
  6. From the
    Alternate
    and
    Fallback
    lists, select a static load balancing method, based on your network environment. Ensure that you select a load balancing method that does not take current server performance or connection load into account.
  7. In the Members area, for the
    Member List
    setting, from the
    Flags
    list, select a flag.
  8. Add wide IPs as members of this load balancing pool.
    The system evaluates the wide IPs (pool members) in the order in which they are listed. A wide IP can belong to more than one pool.
    1. From the
      Wide IP
      list, select a wide IP or type a name that matches an existing wildcard wide IP.
    2. In the
      Service
      field, type the name of a service or protocol.
    3. Click
      Add
      .
  9. Click
    Finished
    .

Creating a pool with pool type SRV

Create a SRV pool type in order to configure the BIG-IP system to load balance global traffic.
  1. On the Main tab, click
    DNS
    GSLB
    Pools
    .
    The Pool List screen opens.
  2. Click
    Create
    .
    The New Pool screen opens.
  3. In the General Properties area, in the
    Name
    field, type a name for the pool.
    Names must begin with a letter, and can contain only letters, numbers, and the underscore (_) character.
    The pool name is limited to 63 characters.
  4. From the
    Type
    list, select the
    SRV
    type.
  5. In the Members area, for the
    Load Balancing Method
    setting, from the
    Preferred List
    , select
    Round Robin
    .
    When deploying this implementation in a lab environment, to determine whether the BIG-IP system returns the DNS response that you expect, try selecting the
    Global Availability
    method and disabling the first pool member in the list.
  6. From the
    Alternate
    and
    Fallback
    lists, select a static load balancing method, based on your network environment. Ensure that you select a load balancing method that does not take current server performance or connection load into account.
  7. Add wide IPs as members of this load balancing pool.
    The system evaluates the wide IPs (pool members) in the order in which they are listed. A wide IP can belong to more than one pool.
    1. In the Members area, for the
      Member
      setting, from the
      Wide IP
      list, select a wide IP or type a name that matches an existing wildcard wide IP.
    2. In the
      Port
      field, type a port number.
    3. Click
      Add
      .
  8. Click
    Finished
    .

An example lw4o6 table

Following is an example of an lw4o6 binding table.
-------------------------- # text_csv # psid_len 1 # # IPv4 IPv6 prefix PSID 10.100.10.211, 2015:a000:0000:0000, 0, 10.100.10.211, 2015:a000:0000:0000, 1, 10.100.10.212, 2015:a000:0000:0001, 0, 10.100.10.212, 2015:a000:0000:0001, 1, 10.100.10.213, 2015:a000:0000:0002, 0, 10.100.10.213, 2015:a000:0000:0002, 1, 10.100.10.215, 2015:a000:0000:0003, 0, 10.100.10.215, 2015:a000:0000:0003, 1, #end file

Creating a pool with pool type MX

Create a MX pool type in order to configure the BIG-IP system to load balance global traffic.
  1. On the Main tab, click
    DNS
    GSLB
    Pools
    .
    The Pool List screen opens.
  2. Click
    Create
    .
    The New Pool screen opens.
  3. In the General Properties area, in the
    Name
    field, type a name for the pool.
    Names must begin with a letter, and can contain only letters, numbers, and the underscore (_) character.
    The pool name is limited to 63 characters.
  4. From the
    Type
    list, select the
    MX
    type.
  5. In the Members area, for the
    Load Balancing Method
    setting, from the
    Preferred List
    , select
    Round Robin
    .
    When deploying this implementation in a lab environment, to determine whether the BIG-IP system returns the DNS response that you expect, try selecting the
    Global Availability
    method and disabling the first pool member in the list.
  6. From the
    Alternate
    and
    Fallback
    lists, select a static load balancing method, based on your network environment. Ensure that you select a load balancing method that does not take current server performance or connection load into account.
  7. Add wide IPs as members of this load balancing pool.
    The system evaluates the wide IPs (pool members) in the order in which they are listed. A wide IP can belong to more than one pool.
    1. In the Members area, for the
      Member
      setting, from the
      Wide IP
      list, select a wide IP or type a name that matches an existing wildcard wide IP.
    2. Click
      Add
      .
  8. Click
    Finished
    .

Creating a wide IP that provides for negative caching

Ensure that at least one global load balancing pool exists in the configuration before you create a wide IP.
Create a wide IP configured in a manner where BIG-IP DNS returns an SOA record that contains a TTL with a Return Code On Failure response. With this configuration, the local DNS servers can cache a negative response and provide faster responses to DNS queries.
  1. On the Main tab, click
    DNS
    GSLB
    Wide IPs
    .
    The Wide IP List screen opens.
  2. Click
    Create
    .
    The New Wide IP List screen opens.
  3. From the
    General Properties
    list, select
    Advanced
    .
  4. In the
    Name
    field, type a name for the wide IP.
    You can use two different wildcard characters in the wide IP name: asterisk (*) to represent several characters and question mark (?) to represent a single character. This reduces the number of aliases you have to add to the configuration.
  5. From the
    Type
    list, select one of these record types for the wide IP:
    NAPTR
    The Name Authority Pointer record, NAPTR, aids in the standardization of Uniform Resource Names (URNs). NAPTR records map between sets of URNs, URLs and plain domain names, and suggest to clients the protocols available for communication with the mapped resource.
    A
    The Address record, or A record, lists the IP address for a given host name.
    SRV
    The Service resource record, SRV, is a pointer with which an alias for a given service is redirected to another domain.
    CNAME
    The Canonical Name resource record, CNAME, specifies an alias or nickname for the official, or canonical, host name.
    AAAA
    The IPv6 Address record, or AAAA record, lists the 128-bit IPv6 address for a given host name.
    MX
    The Mail Exchange resource record, MX, defines the mail system(s) for a given domain.
  6. From the
    Return Code On Failure
    list, select
    Enabled
    .
  7. From the
    RCODE
    list, select one of these options:
    NOERROR (No Error)
    No error condition.
    FORMERR (Query Format Error)
    The name server was unable to interpret the query.
    SERVFAIL (Server Failure)
    The name server was unable to process this query due to a problem with the name server.
    NXDOMAIN (Non Existent Domain)
    The domain name referenced in the query does not exist.
    NOTIMP (Not Implemented)
    The name server does not support the requested kind of query.
    REFUSED (Refuse To Answer)
    The name server refuses to perform the specified operation for policy reasons.
  8. In the
    SOA Negative Caching TTL
    field, type the number of seconds that the local DNS servers consider the Return Code On Failure to be valid.
  9. In the Pools area, for the
    Pool List
    setting, select the pools that this wide IP uses for load balancing.
    The system evaluates the pools based on the wide IP load balancing method configured.
    1. From the
      Pool
      list, select a pool.
      A pool can belong to more than one wide IP.
    2. Click
      Add
      .
  10. Click
    Finished
    .

Implementation result

You now have an implementation in which DNS returns a TTL in a Return Code On Failure for a web site represented by a wide IP in the BIG-IP DNS configuration.