Manual Chapter :
Configuring a TTL in a Return Code On Failure
Applies To:
Show VersionsBIG-IP LTM
- 15.1.9, 15.1.8, 15.1.7, 15.1.6, 15.1.5, 15.1.4, 15.1.3, 15.1.2, 15.1.1, 15.1.0, 15.0.1, 15.0.0, 14.1.5, 14.1.4, 14.1.3, 14.1.2, 14.1.0, 14.0.1, 14.0.0
BIG-IP DNS
- 15.1.9, 15.1.8, 15.1.7, 15.1.6, 15.1.5, 15.1.4, 15.1.3, 15.1.2, 15.1.1, 15.1.0, 15.0.1, 15.0.0, 14.1.5, 14.1.4, 14.1.3, 14.1.2, 14.1.0, 14.0.1, 14.0.0
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.
- On the Main tab, click.The Pool List screen opens.
- ClickCreate.The New Pool screen opens.
- In the General Properties area, in theNamefield, 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.
- From theTypelist, depending on the type of the system (IPv4 or IPv6), select either anAorAAAApool type.
- In the Configuration area, for theHealth Monitorssetting, in theAvailablelist, select a monitor type, and move the monitor to theSelectedlist.Hold the Shift or Ctrl key to select more than one monitor at a time.
- In the Members area, for theLoad Balancing Methodsetting, from thePreferred List, selectRound 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 theGlobal Availabilitymethod and disabling the first pool member in the list.
- From theAlternateandFallbacklists, 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.
- In the Members area, for theMember Listsetting, 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.
- Select a virtual server from theVirtual Serverlist.
- ClickAdd.
- ClickFinished.
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.
- On the Main tab, click.The Pool List screen opens.
- ClickCreate.The New Pool screen opens.
- In the General Properties area, in theNamefield, 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.
- From theTypelist, select theNAPTRtype.
- In the Members area, for theLoad Balancing Methodsetting, from thePreferred List, selectRound 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 theGlobal Availabilitymethod and disabling the first pool member in the list.
- From theAlternateandFallbacklists, 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.
- In the Members area, for theMember Listsetting, from theFlagslist, select a flag.
- 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.
- From theWide IPlist, select a wide IP or type a name that matches an existing wildcard wide IP.
- In theServicefield, type the name of a service or protocol.
- ClickAdd.
- ClickFinished.
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.
- On the Main tab, click.The Pool List screen opens.
- ClickCreate.The New Pool screen opens.
- In the General Properties area, in theNamefield, 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.
- From theTypelist, select theSRVtype.
- In the Members area, for theLoad Balancing Methodsetting, from thePreferred List, selectRound 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 theGlobal Availabilitymethod and disabling the first pool member in the list.
- From theAlternateandFallbacklists, 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.
- 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.
- In the Members area, for theMembersetting, from theWide IPlist, select a wide IP or type a name that matches an existing wildcard wide IP.
- In thePortfield, type a port number.
- ClickAdd.
- ClickFinished.
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.
- On the Main tab, click.The Pool List screen opens.
- ClickCreate.The New Pool screen opens.
- In the General Properties area, in theNamefield, 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.
- From theTypelist, select theMXtype.
- In the Members area, for theLoad Balancing Methodsetting, from thePreferred List, selectRound 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 theGlobal Availabilitymethod and disabling the first pool member in the list.
- From theAlternateandFallbacklists, 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.
- 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.
- In the Members area, for theMembersetting, from theWide IPlist, select a wide IP or type a name that matches an existing wildcard wide IP.
- ClickAdd.
- ClickFinished.
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.
- On the Main tab, click.The Wide IP List screen opens.
- ClickCreate.The New Wide IP List screen opens.
- From theGeneral Propertieslist, selectAdvanced.
- In theNamefield, 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.
- From theTypelist, select one of these record types for the wide IP:NAPTRThe 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.AThe Address record, or A record, lists the IP address for a given host name.SRVThe Service resource record, SRV, is a pointer with which an alias for a given service is redirected to another domain.CNAMEThe Canonical Name resource record, CNAME, specifies an alias or nickname for the official, or canonical, host name.AAAAThe IPv6 Address record, or AAAA record, lists the 128-bit IPv6 address for a given host name.MXThe Mail Exchange resource record, MX, defines the mail system(s) for a given domain.
- From theReturn Code On Failurelist, selectEnabled.
- From theRCODElist, 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.
- In theSOA Negative Caching TTLfield, type the number of seconds that the local DNS servers consider the Return Code On Failure to be valid.
- In the Pools area, for thePool Listsetting, 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.
- From thePoollist, select a pool.A pool can belong to more than one wide IP.
- ClickAdd.
- ClickFinished.
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.