Mitel 6867i Administrator's Manual page 980

Mitel 6800 Series SIP Phone Release 4.2.0 Administrator Guide
DNS QUERY SETTING
PARAMETER –
sip dns query type
DESCRIPTION
FORMAT
DEFAULT VALUE
RANGE
EXAMPLE
A-282
CONFIGURATION FILES
startup.cfg, <mac>.cfg
Specifies the Domain Name Service (DNS) query method to use
when the IP
Phones issue requests for DNS records using one of three methods:
"A" only, SRV & A, and NAPTR & SRV & A.
Integer
1 (SRV & A)
0: A only - The phone issues requests for "A" (Host IP Address)
records from the DNS server to get the IP address, and uses the
default port number of 5060.
1: SRV & A - The phone issues requests for "SRV" (Service
Location Record) records from the DNS server to get the port
number. Most often, the IP address is included in the response from
the DNS server to avoid extra queries. If there is no IP address
returned in the response, the phones send out the request for "A"
records from the DNS server to find the IP address.
2: NAPTR & SRV & A - First, the phone sends "NAPTR" (Naming
Authority Pointer) lookup to get the "SRV" pointer and service type.
For example, if Global SIP transport protocol on the phone is "UDP",
and Proxy server on the phone is "test.mitel.com", then:
• If the NAPTR record is returned empty, the phone will use the
default value "_sip._udp.test.mitel.com" for the "SRV" lookup.
• If the NAPTR record is returned "test.mitel.com SIP+D2U ....
_sip._udp.abc.mitel.com", the phone will use
"_sip._udp.abc.mitel.com" for the "SRV" lookup.
• If the NAPTR record is returned "test.mitel.com SIP+D2T ....
_sip._tcp.test.mitel.com", where the service type TCP
mismatches the phone configured transport protocol "UDP",
the phone will ignore this value and use the default value
"_sip._udp.test.mitel.com" for the "SRV" lookup.
Note: The phone does not use the service type sent by the NAPTR
response to switch its transport protocol, nor does it use the NAPTR
response to determine whether to use a secure or insecure
.
communication path The phone will always use a global sip protocol
that is configured on the phone via configuration files or web user
interface.
After performing NAPTR, the phone sends "SRV" lookup to get the
IP address and port number. If there is no IP address in the "SRV"
response, then it sends out an "A" lookup to get it.
Note: On the phone side, if you configure the phone with a Fully-
Qualified Domain Name (FQDN) proxy and specified port, the phone
always sends "A only" lookups to find the Host IP Address of the
proxy.
sip dns query type: 2