DNS resolution for SIP controller

Last Updated : Jul 18, 2022 |

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.

Warning:

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.