DNS resolution for SIP controller

Last Updated : Apr 17, 2026 |
Prolog information
Metadata
Keywords:
With software version R4.0.11 and later, Avaya J100 Series IP Phones support DNS service to lookup a Fully Qualified Domain Name (FQDN) in the host part of the SIP_CONTROLLER_LIST parameter.
To use FQDN format in SIP proxies, configure FQDN in SIP_CONTROLLER_LIST from all or at least one proxy source, such as LLDP, DHCP, and Settings file. Configure DNS server with these FQDN to resolve to the required IPv4 or IPv6 addresses in A/AAAA records.
You cannot configure a combination of FQDN and IP addresses. If you configure at least one FQDN, the phone ignores all the IP addresses configured in SIP_CONTROLLER_LIST from all sources.
The following table shows the example configurations:
LLDP
DHCP
Settings file
PPM
Aggregate value
SM1- FQDN
SM1- IP
SM2- FQDN
SM2- IP
135.27.151.3x
135.27.151.2x
svsm03.xyz.com
svsm01.xyz.com
10.133.67.x
Not configured
10.133.xx.2
FQDN
svsm01.xyz.com
svsm03.xyz.com
135.27.151.3x
135.27.151.2x
135.27.151.2xx
svsm01.xyz.com
10.133.67.x
svsm02.xyz.com
10.133.xx.2
IP address
10.133.67.x
10.133.xx.2
135.27.151.2xx
135.27.151.2x
135.27.151.3x
135.27.151.3x
135.27.151.2x
135.27.151.2xx
Not configured
10.133.67.x
svsm02.xyz.com
10.133.xx.2
IP address
10.133.67.x
10.133.xx.2
135.27.151.2xx
135.27.151.2x
135.27.151.3x
135.27.151.3x
135.27.151.2x
svsm03.xyz.com
svsm01.xyz.com
10.133.67.x
svsm02.xyz.com
10.133.xx.2
FQDN
svsm01.xyz.com
svsm02.xyz.com
svsm03.xyz.com
135.27.151.3x
135.27.151.2x
svsm03.xyz.com
135.27.151.2xx
svsm01.xyz.com
10.133.67.x
svsm02.xyz.com
10.133.xx.2
FQDN
svsm01.xyz.com
svsm02.xyz.com
svsm03.xyz.com
135.27.151.3x
135.27.151.2x
svsm03.xyz.com
Not configured
10.133.67.x
Not configured
10.133.xx.2
FQDN
svsm03.xyz.com
svsm01.xyz.com
135.27.151.2x
135.27.151.3x
Not configured
10.133.67.x
Not configured
10.133.xx.2
FQDN
svsm01.xyz.com
135.27.151.2x
svsm01.xyz.com
135.27.151.3x
Not configured
10.133.67.x
Not configured
10.133.xx.2
FQDN
svsm01.xyz.com
Note:
If you configure the phone with one or more SIP proxies as FQDN using LLDP, DHCP, or settings file, the phone supports using FQDN from PPM. Otherwise, the phone uses the IP address for SIP proxies from PPM.

Using the web interface and the phone UI to configure SIP controller

If you configure the value for the SIP controller on both the web interface and the Admin menu of the phone, the phone uses the latest configured value.
If you configure at least one FQDN value, the phone uses it. The following table shows the example configuration:
Existing effective SIP controller
Configure value from phone UI
Configure value from web interface
New effective SIP controller
No value
10.133.35.5x
10.133.35.1xx
10.133.35.1xx
10.133.35.1xx
10.133.35.5x
No change
10.133.35.1xx
10.133.35.5x
10.133.35.1xx
10.133.35.5x
j100sm1.xyz.com
No change
j100sm1.xyz.com
j100sm1.xyz.com
j100sm2.xyz.com
No change
j100sm1.xyz.com
j100sm2.xyz.com
j100sm1.xyz.com
j100sm2.xyz.com
No change
10.133.35.1xx
10.133.35.5x
10.133.35.1xx
10.133.35.5x
10.133.35.1xx
10.133.35.5x
No change
j100sm1.xyz.com
10.133.35.1xx
j100sm1.xyz.com
To configure FQDN, use parameter SIP_CONTROLLER_LIST in all IP modes- IPv4, IPv6, or Dual stack.
Avaya Aura® environment does not support the DNS query of NAPTR and SRV records.
From the software version 4.0.12 and later, the phone supports SNI when you configure SIP proxy in FQDN format. The phone sends SNI in HTTPS certificate exchange.
The phone ignores the parameter setting FQDN_IP_MAP when you configure SIP proxy as FQDN for SIP TLS connection.
The phone ignores the FQDN SIP proxy configuration when you configure using the parameter SIP_CONTROLLER_LIST_2.
Other:
When you configure SIP proxies using FQDN and deploy a Branch Session Manager(BSM) in the environment, the J100 phones cannot connect to a configured BSM if the phone reboots during a WAN outage and there is no local DNS server to resolve the BSM FQDN.

Limitation

The phone does not detect the duplicate IP addresses that FQDNs resolve.
For example: If both FQDNs j100sm1.avaya.com and j100sm2.avaya.com resolves into the same IP address 10.133.35.151, the phone does not detect the duplicate IP address, it creates two SIP connections to the same IP address.