Administrator’s Guide for SIP-T2 Series/T4 Series/T5 Series IP Phones
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static.network.dns.query_timeout
[1]
It configures the interval (in seconds) at which the phone retries to resolve a domain
name when the DNS server does not respond.
static.network.dns.retry_times
[1]
It configures the retry times when the DNS server does not respond.
[1]
If you change this parameter, the IP phone will reboot to make the change take effect.
Static DNS Cache
Failover redundancy can only be utilized when the configured domain name of the server is resolved to
multiple IP addresses. If the IP phone is not configured with a DNS server, or the DNS query returns no
result from a DNS server, you can statically configure a set of DNS NAPTR/SRV/A records into the IP
phone. The IP phone will attempt to resolve the domain name of the SIP server with static DNS cache.
Support for negative caching of DNS queries as described in RFC 2308 is also provided to allow faster
failover when prior DNS queries have returned no results from the DNS server.
Topics
Behave with a Configured DNS Server
Static DNS Cache Configuration
Behave with a Configured DNS Server
When the IP phone is configured with a DNS server, it will behave as follows to resolve domain name of
the server:
The IP phone performs a DNS query to resolve the domain name from the DNS server.
If the DNS query returns no results for the domain name, or the returned record cannot be
contacted, the values in the static DNS cache (if configured) are used when their configured time
intervals are not elapsed.
If the configured time interval is elapsed, the IP phone will attempt to perform a DNS query again.
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