ETRN & ODMR

Does your ISP block Port 25 ? Do you have a Dynamic IP address?

Use the Mailkeep service to solve your problems
with the Mailtraq Reverse SMTP Features on this page.

Find out more ...

Reverse SMTP (ETRN/ODMR)

This dialog, accessed via the Options menu in the Console, configures Mailtraq's Reverse SMTP services.
Two client services are available, ETRN and ODMR.

ETRN (Extended TuRN), an extension to the basic SMTP protocol and defined in RFC1985, is primarily intended for use between an intermittently connected host (typically on a dial-up connection to the Internet but with a static IP address) and the SMTP mail service of their Internet Service Provider (ISP). ETRN mail delivery is effected by Mailtraq sending ETRN commands to a remote mail server requesting that it deliver any messages held in its outbound SMTP mail queue. If any messages for the Mailtraq host are being queued, the remote server despatches them to Mailtraq by opening new SMTP sessions as required. The SMTP session containing the ETRN command itself is always closed immediately after acknowledgement for security reasons. To make use of this facility in Mailtraq the remote server must be specifically configured to enable ETRN message processing and this should be confirmed, usually with the service personnel of an ISP, before attempting to use ETRN.

ODMR (On-Demand Mail Relay), an extension to the basic SMTP protocol and defined in RFC2645, is primarily intended for use between an intermittently connected host (typically on a dial-up connection to the Internet with a dynamically assigned IP address) and the SMTP mail service of their ISP. Using ODMR, mail delivery is effected by Mailtraq authenticating itself to the remote mail server and requesting any mail waiting for specific domains. On completion of that process, the SMTP roles reverse on the same connection, Mailtraq becoming the SMTP server instead of the SMTP client and the remote mail server becoming the SMTP client instead of the SMTP server. The remote mail server then delivers any waiting messages down the authenticated connection. To make use of this facility in Mailtraq the remote server must be specifically configured to enable ODMR message processing and this should be confirmed, usually with the service personnel of an ISP, before attempting to use ODMR.

ODMR provides encrypted authentication and is significantly more secure than ETRN. Wherever possible, therefore, ODMR should be used in preference to ETRN or other techniques, e.g. sending FINGER commands containing passwords to the remote SMTP server.

Configuration Guide

ETRN Agent Configuration

The ETRN Agent Configuration tab, which appears on the ETRN Agent Configuration dialog, configures the detail properties of an ETRN Agent.

Enable this Agent
Check this option to activate this ETRN agent. If unchecked, the Server entry in the Mail Collection Agents tab displays the suffix "(Disabled)".

Server
Enter the host name of the remote ETRN mail server.

Port
Enter the port number, default is port 25 as for SMTP, on which the remote ETRN server listens for connections.

Parameters/Domains
This field is implementation specific and may contain passwords, keywords, the domains for which mail is to be released from the remote ETRN mail queue, etc. If in doubt about the correct syntax, consult the help desk of, or the technical documentation provided by, your ISP.

Initiate every...
Check this option and enter the period in minutes, defaulting to 10, after which Mailtraq should issue another ETRN command to the remote ETRN mail server whilst online. If preferred, ETRN commands may be initiated manually using Send on the Mail Collection Agents tab.

Note
For those with intermittent dial-up connections, the ETRN initiation period should be significantly greater than the idle timeout of their current Dial-up Schedule otherwise, allowing time for subsequent mail delivery, the connection may never be idle for sufficient time to trigger the timeout.

ODMR Agent Configuration

The ODMR Agent Configuration tab, which appears on the ODMR Agent Configuration dialog, configures the detail properties of an ODMR Agent.

Enable this Agent
Check this option to activate this ODMR agent. If unchecked, the Server entry in the Mail Collection Agents tab displays the suffix "(Disabled)".

Server
Enter the host name of the remote ODMR mail server.

Port
Enter the port number, default is port 366, on which the remote ODMR server listens for connections.

Account
Enter the account identifier, which may be any alphanumeric string, required by the remote ODMR server for authentication purposes.

Parameters/Domains
This field is implementation specific and may contain passwords, keywords, the domains for which mail is to be released from the remote ODMR mail queue, etc. If in doubt about the correct syntax, consult the help desk of, or the technical documentation provided by, your ISP.

Password
Enter the account password, which may be any alphanumeric string, required by the remote ODMR server for authentication purposes.

SMTP Service for Inbound Mail
If multiple instances of the SMTP Service have been configured in the Console, select the required SMTP service instance from the drop list. Click on the Edit button to review the settings for the selected SMTP service. In particular, ensure that the Access Control tab permissions do not deny access to the IP address of the remote ODMR server.

Initiate every...
Check this option and enter the period in minutes, defaulting to 10, after which Mailtraq should issue another ODMR command to the remote ODMR mail server whilst online. If preferred, ODMR commands may be initiated manually using Send on the Mail Collection Agents tab.

Note
For those with intermittent dial-up connections, the ODMR initiation period should be significantly greater than the idle timeout of their current Dial-up Schedule otherwise, allowing time for subsequent mail delivery, the connection may never be idle for sufficient time to trigger the timeout.

Mailtraq Highlights...
SMTP Server	IMAP Server
POP3 Server	Proxy Server
Webmail Server	Mailing-list Server
Groupware Services	Spam and Virus control