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Network | Listeners | Dialup
# Dialup Mail Receiving TCP Activity Schedule Serving LAN Clients The CommuniGate Pro Server can work on a site that only has a dial-up Internet connection. It allows LAN users to access their mail and to submit messages without generating any Internet TCP traffic, and it allows the System Administrator to specify the Schedule for Internet (dialup) TCP/IP activity.

## Mail Receiving

Dial-up systems are not connected to the Internet all the time. As a result, most of the time other systems cannot send mail directly to your dial-up server.

You can use three methods to receive incoming E-mail messages:

- store all mail in a Unified Domain-Wide Account on your ISP server, and retrieve it from there periodically, using the RPOP module.
- specify your ISP mail server as your mail backup server, and use the SMTP Remote Queue Starting (ETRN) feature to retrieve mail using the SMTP module.
- specify your ISP mail server as your mail server (main MX), and use the SMTP ATRN feature to retrieve mail using the SMTP module. The ISP mail server should be able to handle the ATRN requests. If the ISP server is a CommuniGate Pro Server, too, it should be configured to hold mail for your Domain and to accept ATRN commands from your Server.

Your Server should have a static IP address to be able to receive mail via SMTP (using ETRN). If your ISP assigns you an IP address dynamically, and each time your Server can get a different IP address, retrieving mail using the SMTP ATRN module or the RPOP module are the only choices.

## TCP Activity Schedule

The Server Administrator can specify when and how often the Server is allowed to generate outgoing TCP/IP traffic. This helps to limit the time your Internet dial-up link is up.

The TCP Activity Schedule is checked within the SMTP and RPOP modules and can be used to limit their activities.

Use the WebAdmin Interface to configure the TCP Activity Schedule. Open the Network pages in the Settings realm, and follow the Schedule link.

IP Activity Schedule
Log Level:
Day(s) of Week | When | Pause
--- | --- | ---
| - |
| - |
| - |

`Log Level`
  Use this setting to specify what kind of information the TCP Activity Schedule component should put in the Server Log. Usually you should use the `Major` (session starts) levels. But when you experience problems with the TCP Activity Schedule component, you may want to set the Log Level setting to `Low-Level` or `All Info`: in this case the schedule calls and schedule processing details will be recorded in the System Log as well.

  The TCP Activity Schedule component System Log records are marked with the `TCP` tag.

`Day of Week`
  This setting specifies the week days when this TCP Scheduler element should be used.
`When`
  This setting specifies the time period when outgoing TCP Activity is allowed.

  If the first time setting is larger than the second one, it specifies an "over-the-midnight" time period: `19:30 - 07:30` means from 19:30 till midnight and from midnight till 7:30 in the morning.

`Pause`
  This setting specifies the minimal time interval between successive outgoing "TCP sessions".

You can remove elements from the Schedule by settings the Day of Week option to `Never`, and you add elements to the Schedule by changing the Day of Week option value in the last dummy (`Never`) element.

## Serving LAN Clients

Your LAN client mailers can generate outgoing Internet activity when they submit messages via SMTP, and this can force your dial-up link to go up every time they send a message.

To avoid this problem:

- make sure that your own CommuniGate Pro Server, not the ISP mail server is specified in the client mailer settings as the "outgoing mail server";
- make sure that IP addresses of all your LAN Clients are included into the Client Hosts list;
- make sure that SMTP module Verify Return-Path for option is set to `non-clients` or `nobody`.

CommuniGate® Pro Guide. Copyright © 1998-2012, Stalker Software, Inc.