Spectralink 84-Series Series Wireless Telephones Administration Guide
1725-86984-000_P.docx
September 2016
259
If the initial DNS query returns no results for the hostname or cannot be contacted, then
the values in the static cache are used for their configured time interval.
After the configured time interval has elapsed, a resolution attempt of the hostname will
again result in a query to the DNS.
If a DNS query for a hostname that is in the static cache returns a result, the values from
the DNS are used and the statically cached values are ignored.
When a handset is not configured with a DNS server, it will behave as follows
An attempt to resolve a hostname that is within the static DNS cache will always return
the results from the static cache.
Support for negative DNS caching as described in RFC 2308 is also provided to allow faster
failover when prior DNS queries have returned no results from the DNS server
.
For more
information, go to
http://tools.ietf.org/html/rfc2308
.
Configuration File Changes
Configuration changes can be performed centrally at the boot server:
Central
(boot server)
Configuration file:
sip.cfg
Specify DNS NAPTR, SRV, and A records for use when the handset
is not configured to use a DNS server.
For more information, refer to DNS Cache <dns/
>
.
DNS Cache <dns/>
In the tables below, a maximum of 12 entries of NAPTR, SRV, and A record can be added.
This attribute includes:
•
NAPTR <NAPTR/
>
attribute
•
SRV <SRV/
>
•
A <A/
>
NAPTR <NAPTR/>
Attribute
Permitted Values
Default
Interpretation
dns.cache.NAPTR.x.name
domain name string
Null
The domain name to which this resource record
refers.
dns.cache.NAPTR.x.ttl
0 to 65535, seconds
300
Specifies the time interval that the resource
record may be cached before the source of the
information should again be consulted.
dns.cache.NAPTR.x.order
0 to 65535
0
A 16-bit unsigned integer specifying the order in
which the NAPTR records must be processed to
ensure the correct ordering of rules.
dns.cache.NAPTR.x.
pref erence
0 to 65535
0
A 16-bit unsigned integer that specifies the
order in which NAPTR records with equal
"order" values should be processed, low
numbers being processed before high numbers.