I have provisioned an Azure SQL Database server and configured the server security settings as follows: Public access : Selected "Selected Networks" Firewall rule : Whitelisted public IP addresses to allow access to the database However, when I attempt to "telnet" to the server from a PC with a public IP that is not whitelisted, the connection still goes through. What can I do to prevent telnet access while maintaining the same configurations?

What is allowing telnet to connect is the Azure SQL Public Gateway not the Azure SQL Database itself. This is an expected behavior in Azure Database. Port 1433 is required to provide a variety of Azure services, and this is by design. So, telnet is reaching a public gateway that is open for everyone and is not reaching the actual database, Read here about the gateway

Issue with Unrestricted Telnet Access to Azure SQL Database Server Despite Firewall Rules

Mithila Lishan 166

I have provisioned an Azure SQL Database server and configured the server security settings as follows:

Public access: Selected "Selected Networks"
Firewall rule: Whitelisted public IP addresses to allow access to the database

However, when I attempt to "telnet" to the server from a PC with a public IP that is not whitelisted, the connection still goes through.

What can I do to prevent telnet access while maintaining the same configurations?

Sai Raghunadh M 560 Reputation points Microsoft Vendor

2024-09-20T15:24:51.8633333+00:00

Hi @Mithila Lishan,

Just checking in to see if the below answer provided by @Alberto Morillo helped.

If this answers your query, do click Accept Answer and Yes for was this answer helpful. And, if you have any further query do let us know.
Mithila Lishan 166 Reputation points

2024-09-20T17:16:53.07+00:00

Hi @Sai Raghunadh M I need more time to understand and verify below answer is solve my question or not
Sai Raghunadh M 560 Reputation points Microsoft Vendor

2024-09-23T07:55:55.05+00:00

Hi @Mithila Lishan,

We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.
Sai Raghunadh M 560 Reputation points Microsoft Vendor

2024-09-24T10:14:14.59+00:00

Hi @Mithila Lishan,

We haven’t heard from you on the last response and was just checking back to see if you have a resolution yet. In case if you have any resolution please do share that same with the community as it can be helpful to others. Otherwise, will respond with more details and we will try to help.

Accepted answer

Alberto Morillo 33,956 Reputation points MVP

2024-09-20T02:49:50.2766667+00:00

What is allowing telnet to connect is the Azure SQL Public Gateway not the Azure SQL Database itself. This is an expected behavior in Azure Database. Port 1433 is required to provide a variety of Azure services, and this is by design.

So, telnet is reaching a public gateway that is open for everyone and is not reaching the actual database, Read here about the gateway
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Issue with Unrestricted Telnet Access to Azure SQL Database Server Despite Firewall Rules

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