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 not recommended because the receiving mail server may get overloaded and think that it is under attack, as occurs 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 you add, for example, an entry of bellsouth.net, "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 one connection per domain.

ListManager uses a technology called "connection reuse" that allows it to reuse a network connection, rather than disconnecting and re-connecting for each message sent. 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 other programs would be with 100 connections. This is also why we recommend that you do not increase the number of allowed connections per IP address to more than 10 unless you are certain the mail server can handle this load and will not ban you for overloading their system.

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

Simultaneous Connections

Enter the connection limit desired. Note that when entering domain limits, only integers can be entered. You can enter a minimum limit of 1 and a maximum of 100. Note: If you intend to use a setting higher than 10, first ensure that the mail server can handle the load.

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

Messages Per Connection

Determines how many messages can be sent on a single connection.

Connections Per Hour

Determines how many connections you can make per hour.

Example:

You choose the following settings;

Simultaneous Connections:  1

Messages Per Connection:  100

Connections Per Hour:     12 (this determines that a new connection will be made every five minutes)

1. ListManager opens a connection and sends 100 messages, then closes the connection.

2. At Minute # 5, the connection reopens, ListManager sends another 100 messages, and then the connection closes.

3. At Minute # 10, the connection reopens, ListManager sends another 100 messages, and then the connection closes.

This cycle repeats until all messages have been sent.

Note: These amounts are approximate. The exact number of messages sent may vary depending on several factors, including the response of the mail server.

Notes

• If you leave the Messages Per Connections and Connections Per Hour settings blank, the amounts for these settings default to "unlimited."
• All settings are per IP address of a destination mail server. If a company has more than one mail server (for example, Yahoo has eight), your sending speed increases accordingly.
• If you use a relay host, all settings on this page are ignored and mail is sent based on the Maximum Connections settings on this page:

   Utilities: Administration: Server: Server Settings: Network Settings: Relay Hosts

• If one or more relay servers are defined, domain connection limits have no effect

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