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
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.
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
No part of this program may be reproduced or transmitted in any form or
by any means, electronic or mechanical, including photocopying,
recording, or information storage and retrieval systems, for any
purpose other than the purchaser's personal 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 2016-04-22 net dns-resolver(1)