Administrator’s Guide for Akuvox SP-R5xP IP Phones
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SIP Server Domain Name Resolution
If a domain name is configured for a SIP server, the IP address(es) associated with that domain
name will be resolved through DNS as specified. The DNS query involves SRV, which allows the
IP phone to adapt to various deployment environments.
If an explicit port (except 0) is specified and the transport type is set to DNS-SRV, A query will
be performed only. If a SIP server port is set to 0 and the transport type is set to DNS-NAPTR,
NAPTR and SRV queries will be tried before falling to A query. If no port is found through the
DNS query, 5060 will be used.
The following details the procedures of DNS query for the IP phone to resolve the domain
name (e.g., akuvox.pbx.com) of working server into the IP address, port and transport
protocol.
SRV (Service Location Record)
The IP phone performs an SRV query on the record returned from the NAPTR for the host
name and the port number. Example of SRV records:
Priority Weight Port Target
IN SRV 0 1 5060 server1.akuvox.pbx.com
IN SRV 0 2 5060 server2.akuvox.pbx.com
Parameters are explained in the following table: