net dns-resolver
net dns-resolver(1) BIG-IP TMSH Manual net dns-resolver(1)
NAME
resolver - Configures a DNS resolver on the BIG-IP(r) system.
MODULE
net dns-resolver
SYNTAX
Configure the DNS resolver component using the syntax in the following sections.
CREATE/MODIFY
create [name]
modify [name]
options:
answer-default-zones [yes | no]
app-service [[string] | none]
cache-size [integer]
description [string]
forward-zones [add | delete | modify | replace-all-with] {
[ [zone-name] ] {
options:
nameservers [add | delete | replace-all-with] {
[ [IPv4address:port] | [IPv6address.port] ]
}
nameservers none
}
forward-zones none
nameserver-ttl [integer]
nameserver-min-rtt [integer]
randomize-query-name-case [yes | no]
route-domain [name]
use-ipv4 [yes | no]
use-ipv6 [yes | no]
use-tcp [yes | no]
use-udp [yes | no]
DISPLAY
list
list [ [ [name] | [glob] | [regex] ] ... ]
options:
all-properties
non-default-properties
one-line
show [name]
reset-stats
DELETE
delete [name]
DESCRIPTION
You can use the dns-resolver component to configure and view information about a DNS Resolver object. A DNS resolver
performs recursive resolution to fill its cache.
Important: When sizing caches, consider the total amount of memory available and how you wish to allocate memory for DNS
caching. Note that cache sizing values are per-TMM process; therefore, a platform with eight TMMs consumes the amount of
memory set for the Resolver object times eight.
Important: DNS Resolver objects use the DNS root nameservers published by InterNIC.
EXAMPLES
list
Displays the properties of the DNS Resolver myRes.
OPTIONS
answer-default-zones
Specifies whether the resolver answers queries for default zones: localhost, reverse 127.0.0.1 and ::1, and AS112
zones. The default value is no.
app-service
Specifies the name of the application service to which this dns-resolver belongs. The default value is none. Note: If
the strict-updates option is enabled on the application service that owns the object, you cannot modify or delete this
dns-resolver. Only the application service can modify or delete this dns-resolver.
cache-size
Specifies the maximum cache size in bytes of the DNS Resolver object. The default value is 5767168.
The BIG-IP system caches the supporting records in a DNS response in the resource record cache. After the maximum size
of the cache is reached, when new or refreshed content is added to the cache, the expired and older content is removed
from the cache. A higher maximum size allows more DNS responses to be cached and increases the cache hit percentage. A
lower maximum size forces earlier eviction of cached content, but can lower the cache hit percentage.
description
User defined description.
forward-zones
Adds, deletes, modifies, or replaces a set of forward zones on a DNS Resolver, by specifying zone name(s). A given
zone name should only use the symbols allowed for a fully qualified domain name (FQDN), namely ASCII letters a though
z, digits 0 through 9, hyphen -, and period .. For example site.example.com would be a valid zone name.
A DNS Resolver configured with a forward zone will forward any queries that resulted in a cache-miss (the answer was
not available in the cache) and which also match a configured zone name, to the nameserver specified on the zone. If
no nameservers are specified on the zone, an automatic SERVFAIL is returned. When a forward zone's nameserver returns
a valid response to the DNS Cache, that response is cached and then returned to the requestor.
nameservers
Adds, deletes, modifies, or replaces a set of nameservers in a forward zone on a DNS Resolver. A nameserver is
represented by an IPaddress and port in the format [IPv4:port] or [IPv6.port], for example 10.10.10.10:53 or
2001::1:ff.53, respectively.
If more than one nameserver is listed for a given forward zone, a matching query will be sent to the nameserver
that is currently deemed the most responsive (based on RTTs). If no response is received within a certain window
of time, the DNS Resolver will resend the query to another nameserver with an increased wait window, until a
response is received.
glob Displays the items that match the glob expression. See help glob for a description of glob expression syntax.
name Specifies a unique name for the component. This option is required for the commands create, delete, and modify.
nameserver-ttl
Specifies the time to live, in seconds, for DNS nameservers in the cache. The default value is 900 seconds.
randomize-query-name-case
Specifies whether the resolver randomizes the case of query names. The default value is yes.
regex
Displays the items that match the regular expression. The regular expression must be preceded by an at sign (@[regular
expression]) to indicate that the identifier is a regular expression. See help regex for a description of regular
expression syntax.
route-domain
Specifies the route domain the resolver uses for outbound traffic. The default value is the default route domain.
use-ipv4
Specifies whether the resolver sends DNS queries to IPv4 addresses. The default value is yes.
use-ipv6
Specifies whether the resolver sends DNS queries to IPv6 addresses. The default value is yes.
use-tcp
Specifies whether the resolver can send queries over the TCP protocol. The default value is yes.
use-udp
Specifies whether the resolver can send queries over the UDP protocol. The default value is yes.
SEE ALSO
create, delete, edit, glob, list, show, modify, regex, tmsh
COPYRIGHT
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use, without the express written permission of F5 Networks, Inc.
F5 Networks and BIG-IP (c) Copyright 2009-2013, 2016. All rights reserved.
BIG-IP 2021-12-07 net dns-resolver(1)