Utilities: Administration: Server: Server Settings: Domain Connection Limits

By default ListManager will only open 10 connections to any given TCP/IP address. Opening more connections than this is generally not recommended because the receiving mail server may get overloaded and can think that it is under attack, such as is done with a denial-of-service attack. However, some mail servers have instituted anti-spam measures that trigger warnings at even less connection limits, such as 2. So it may be useful, on a case-by-case basis, to be able to change how many connections ListManager opens to a given host.

This feature allows the number of connections to a specific domain to be configured. By default there are no domains listed, so the default of 10 connections per IP address is used. If an entry is added, such as to bellsouth.net of 2, then any connections that go to a bellsouth.net computer will only open as many as two connections. Computer names 'above' the specified domain will also respect these limits, so in this example, a host of albert.bellsouth.net will also be limited to two connections. The minimum setting allowed is 1 connection per domain.

ListManager uses a technology called "connection reuse" that allows it to reuse a network connection, rather than disconnecting and re-connecting. This technology allows a large amount of mail to be delivered efficiently without requiring a large number of connections. Thus, ListManager may be more efficient in sending mail with ten connections than would be other programs with 100 connections. Therefore, it is again recommended that you do not increase the number of allowed connections per IP address to be more than 10, unless you are certain that the mail server can handle this load and will not ban you for overloading their system.

Creating a new Domain Limit

To create a new domain limit, click the create new limit button:

Domain

Enter the domain name for which you would like to set a limit.

For example: aol.com

Connection Limit

Enter the connection limit desired. Note that when entering domain limits, only integers can be entered. A minimum limit of "1" and a maximum of "32767" (a number this high should never be entered) must be entered. If you try to enter a number outside of this range, ListManager will not accept it and will warn you of the problem.

To edit a domain limit, click on the link to the domain, make your changes, and save. Note that you can also copy, delete, or export these limits from ListManager, using the blue disc symbol in the upper right hand corner of the page.

This setting works in conjunction with DNS Bypass settings, in case any high volume providers force high volume email via a separate server.

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1. Utilities: Administration: Server: Server Settings