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I have an Azure AO AG which consists of three servers (all WS-2019 & SQL-2019CU3):

  • A - Subnet 1 - Principal Server (Sync)
  • B - Subnet 1 - Secondary Server (Sync)
  • C - Subnet 2 - Secondary Server (Async)

I have created a DNN Listener on the resource which looks to be up an running but when I connect to the Listener it resolves to server C. I have confirmed that in both the cluster and AG, server A is the principal. I have tried failing over to server B which seems to work fine but the listener still only resolves to Server C.

I pulled out the Cluster Logs and I have a warning that jumped out to me that does not seem to appear on google:

2020/11/12-15:27:48.720 WARN [RES] Distributed Network Name <6789>: Configuration: Obtaining exclude networks failed with error 2.

Lickrob
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1 Answers1

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Default 1433 SQL port is not supported by DNN listener if SQL server uses this port. Additionally, In case there are multiple AGs with DNN listeners in scope of single cluster, every DNN listener should be configured using unique custom port. The custom port should be added to firewall exceptions on all AG nodes. When connecting using SSMS, it is necessary to specify custom port that was configured for DNN listener in format: , It is also better to explicitly specify AG database in SSMS connection properties and MultiSubnetFailover=True in Additional Connection parameters. That worked for me.

Sergei

serjdag
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