Set connection limits for POP3

Applies to: Exchange Server 2013

You can use the EAC or the Shell to manage POP3 connection limits for your organization.

When you specify connection limits for POP3, you can select connection limits for the server, an IP address, or a specific user.

For additional information related to POP3, see POP3 and IMAP4 in Exchange Server 2013.

What do you need to know before you begin?

• Estimated time to complete: 5 minutes.

• You need to be assigned permissions before you can perform this procedure or procedures. To see what permissions you need, see the "POP3 settings" entry in the Clients and mobile devices permissions topic.

• For information about keyboard shortcuts that may apply to the procedures in this topic, see Keyboard shortcuts in the Exchange admin center.

Tip

Having problems? Ask for help in the Exchange forums. Visit the forums at Exchange Server.

Use the EMC to set POP3 connection limits for a server, an IP address, or a user

1. In the EAC, navigate to Servers > Servers.

2. In the list of servers, select the Client Access server, and then click Edit .

3. On the server properties page, click POP3.

4. Scroll down and click More options.

5. Under Connection limits, use the following settings:

   • Maximum connections: Specifies the total number of connections the specified server will accept. This includes authenticated and unauthenticated connections. The default value is 2,147,483,647. The possible values are from 1 through 2,147,483,647.

   • Maximum connections from a single IP address: Specifies the number of connections that the server will accept from a single IP address. The default value is 2,147,483,647. The possible values are from 1 through 2,147,483,647.

   • Maximum connections from a single user: Specifies the maximum number of connections that the server will accept from a particular user. The default value is 16. The possible values are from 1 through 2,147,483,647.

   • Maximum command size (bytes): specifies the maximum size of a single command. The default size is 512. The possible values are from 40 through 1,024.

6. Click Apply, and then click OK to save your changes.

After you set connection limits, you must restart the POP3 services. For information about how to restart the POP3 services, see Start and stop the POP3 services.

Use the Shell to set POP3 connection limits for a server, an IP address, or a user

This example sets the connection limit for a server named CAS01.

Set-PopSettings -Server CAS01 -MaxConnections Value

This example sets the connection limit for an IP address to a server named CAS01.

Set-PopSettings -Server CAS01 -MaxConnectionsFromSingleIP Value

This example sets the connection limit for a user.

Set-PopSettings -MaxConnectionsPerUser Value

This example sets the maximum command size.

Set-PopSettings -MaxCommandSize Value

After you set connection limits, you must restart the POP3 services. For information about how to restart the POP3 services, see Start and stop the POP3 services.

For more information about syntax and parameters, see Set-PopSettings.

How do you know this worked?

To verify that you've successfully set connection limits, do one of the following:

1. In the EAC, navigate to Servers > Servers.

2. In the list of servers, select the Client Access server, and then click Edit .

3. On the server properties page, click POP3.

4. Scroll down and click More options.

5. Under Connection limits, verify the connection settings are correct.

Or

1. Run the following command in the Shell.

   Get-PopSettings | format-list
   

2. Verify the connection settings are correct.

For more information

After you set POP3 connection limits for a server, an IP address, or a user, you may also want to:

Enable POP3 in Exchange 2013

Set connection time-out limits for POP3