HP TCP/IP Services for OpenVMS

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18.6.7 Specifying Handling of Spam Events

Whenever the TCP/IP Services SMTP server disconnects a link with a client as a result of the Antispam checking, it generates an event message. You can control the way events are handled using the procedures in the following sections. Reporting Spam Events

You can customize the SMTP server to report a spam event in the following ways. The SMTP server can:

To configure the way SMTP reports the event, use the SPAM-Action field in SMTP.CONFIG. The legal values are:

You can specify multiple values for the SPAM-Action field. For example:


This example causes both OPCOM and accounting messages to be sent for each spam event. To disable spam event reporting, enter a value of NONE for SPAM-Action in SMTP.CONFIG, as follows:

SPAM-Action: NONE Configuring Spam Security

When the SMTP server disconnects the link with the client because of the Antispam checking, it sends a message back to the client. The text of the message is controlled by the Security field in SMTP.CONFIG. The legal values for this field are: Specifying the Spam Rejection Text

You can specify the rejection text message to be sent to the client. The field names for these options end in "-Text", and the values for them must be a single line of text. These fields override the default text associated with the specific spam event.

The following are the fields and default messages for the SECURE option:

The following are the fields and default messages for the FRIENDLY option:

You can change one or more of the default messages by including the field and your message for a value. This will override the default setting for that field. For example:

Unbacktranslatable-IP-Text: Your IP address is unbacktranslatable. SPAMMER! 

18.7 Managing SMTP Send-From-File (SFF)

SMTP allows you to create a mail message in a file and send it to the SMTP mailer to be delivered with headers you specify. Using SFF, you can create automated tools that compose and send mail messages.

SFF is also useful for forwarding nontext (MIME) files because it prevents the mailer from encapsulating the MIME and SMTP headers in the body of a new mail message. In this way, SMTP functions like the redirect command on your personal computer.

18.7.1 SFF Security Measures

The ability to create messages with arbitrary headers could be used to spoof message headers. To limit this, SFF adds a Received: header to the headers you supply. This tells you the origin of an attempted spoofed message.

You can invoke SFF from an application or from DCL, as described in the following sections.

18.7.2 Invoking SFF from an Application

TCPIP$SMTP_MAILSHR.EXE contains a routine called TCPIP$SMTP_SEND_FROM_FILE. This routine is declared as follows:

unsigned int TCPIP$SMTP_SEND_FROM_FILE(infile_name, logfd, log_level) 
char *infile_name; 
FILE *logfile_name; 
int log_level; 

The parameters for this routine are:

To call the routine, link with TCPIP$SMTP_MAILSHR.EXE/SHARE.

18.7.3 Invoking SFF from DCL

The SMTP_SFF command allows you to invoke SFF. To define SMTP_SFF as a foreign command so that you can use it from DCL, enter the following command:


This command takes UNIX style parameters and passes them to SFF.

The command format is:

SMTP_SFF infile_name [-log logfile_name] [-loglevel log_level] 

The parameters to this command are:

18.8 Disabling SMTP Outbound Alias

Users can specify an outbound alias that is applied to mail as it is sent and specifies the network address to which a reply will be sent. The outbound alias is defined using the TCPIP$SMTP_FROM logical, which is described in the HP TCP/IP Services for OpenVMS User's Guide.

To disable outbound alias processing (preventing the use of the TCPIP$SMTP_FROM logical), define the following system logical:


18.9 Solving SMTP Problems

To isolate an SMTP problem, follow these steps:

  1. Check the directory SYS$SPECIFIC:[TCPIP$SMTP] for the following log files:
    Purge the directory regularly.
  2. Use the TCPIP$SMTP_LOG_LEVEL logical, as described in Section 18.5.
  3. Check the mail in the TCPIP$SMTP account.
    Forward TCPIP$SMTP mail to the SYSTEM account for monitoring. By default, remote login to TCPIP$SMTP is not allowed.
  4. Check the directory SYS$SPECIFIC:[TCPIP$SMTP] for lost mail.
    If an incoming mail message was undeliverable and the error message was also undeliverable, the SMTP control file is left in this directory, not in the queue.
  5. Check the consistency of the SMTP queues against the directories with the SMTP utility files.
    Enter the ANALYZE MAIL command (see Section 18.9.1).

18.9.1 Verifying SMTP Control Files

Use the ANALYZE MAIL command to verify the correspondence of the SMTP queues with SMTP control files. This command does the following:

The following examples show how to use the ANALYZE MAIL command:

  1. The following command encounters a problem, displays a description and solution, and then requests confirmation before fixing each record.

    %TCPIP-E-ANA_SUP_BADIICGSIZE, Problem: Bad initial inode cell 
    group size: bad_value
    Solution: Will be replaced by 
    default size: good_value
            CONFIRM [Y/N/G]: 

  2. The following command creates a summary of SMTP entries and control files for user DRAKE.

    %TCPIP-I-ANA_NOENTR, no queue entry found for file 
    %TCPIP-I-ANA_COMPLE, ANALYZE completed on node DODO 
    %TCPIP-I-ANA_FEPAIR, found 0 file-queue entry pairs 
    %TCPIP-I-ANA_DELQEN, deleted 0 queue entries 
    %TCPIP-I-ANA_FILNOQ, found 1 files with no queue entries 
    %TCPIP-I-ANA_FILHLD, holding 0 files in directory 
    %TCPIP-I-ANA_FILDEL, deleted 0 files from the Postmaster directory 
    %TCPIP-I-ANA_SUBFIL, submitted 0 files to the generic queue 
    %TCPIP-I-ANA_FILACE, encountered 0 file access errors 
    %TCPIP-I-ANA_NONCFF, found 0 non-unknown files in Postmaster directory 
    %TCPIP-I-ANA_FILCOR, found 0 corrupted CF files in Postmaster directory 

  3. The following command:


18.9.2 Slow Antispam Checking

The operational speed of the SMTP Antispam feature depends on the relative health of the DNS server. A malfunctioning DNS server can slow the operation of SMTP Antispam checking.

Chapter 19
Configuring and Managing the POP Server

The Post Office Protocol (POP) server and the Simple Mail Transfer Protocol (SMTP) server software work together to provide reliable mail management in a client/server environment.

The POP server acts as an interface to the mail repository. It accepts and stores mail messages for you, even when your client system is not connected, and forwards those messages to you at your request. POP is used mostly by PC clients to ensure that mail is received and retained even when the system is not connected to the network.

After the POP server is enabled on your system, you can modify the default characteristics by defining logical names.

This chapter reviews key POP concepts and describes:

19.1 Key Concepts

The POP server is an implementation of the Post Office Protocol Version 3 server (the public domain IUPOP3 server) specified in RFC 1725.

The POP server is intended to be used as a mail repository for:

With POP, mail is delivered to a shared mail server, and a user periodically downloads unread mail. Once delivered, the messages are deleted from the server.

The POP server is assigned port 110, and all POP client connections are made to this port.

The following sections review the POP process and describe how the TCP/IP Services software implements POP. If you are not familiar with POP, refer to RFC 1725 or introductory POP documentation for more information.

19.1.1 POP Server Process

The POP server is installed with SYSPRV and BYPASS privileges and runs in the TCPIP$POP account, which receives the correct quotas from the TCPIP$CONFIG procedure. The POP server is invoked by the auxiliary server.

The POP server uses security features provided in the protocol and in the OpenVMS operating system, as well as additional security measures. These methods provide a secure process that minimizes the possibility of inappropriate access to a user's mail file on the served system.

You can modify the POP server default characteristics and implement new characteristics by defining the system logical names outlined in Section 19.3.

19.1.2 How to Access Mail Messages from the POP Server

To access mail messages from the POP server, you configure a user name and password, or the POP shared secret-password string, into your client mail application.

Your client system opens the TCP connection and attempts to access the server by entering applicable POP commands such as USER (user name) and PASS (password), or APOP (shared secret password). In addition, POP supports the UID command, which some POP clients use, where the UID (user identification) that POP creates for each mail message is a concatenation of the user name and the date of arrival.

Once your client system opens the TCP connection, the POP server issues the following greeting:

+OK  POP server ready TCPIP V5.1 [hostname and IP_Address]

By default, the POP server reads mail from the user's OpenVMS NEWMAIL folder. If you do not instruct the POP server to delete the mail, the server either moves the mail to the MAIL folder (if the logical name TCPIP$POP_USE_MAIL_FOLDER is defined) or keeps it in the NEWMAIL folder (if the logical name TCPIP$POP_LEAVE_IN_NEWMAIL is defined). These logical names are described in Section 19.3.

19.1.3 How the POP Server Initiates and Manages a TCP Connection

The POP server starts the service by listening on TCP port 110. The client initiates a connection when it wants to make use of the POP service. The POP server sends either a greeting message confirming the connection (a message with the +OK prefix) or a message that the connection was not successful (a message with the -ERR prefix).

POP permits only two user name and password authorization attempts per TCP connection. After the second failure, POP closes the connection. Once connected, the client and server exchange commands and responses.

When the POP server detects a blocked TCP connection, it suspends output to the connection for 2 seconds to allow it to unblock. Upon retry, if the connection is still blocked, the POP server waits 4 seconds before trying again, and so on up to 32 seconds. If the connection is still blocked after 32 seconds, the POP server shuts down the connection and sends an error message to the log file, allowing other client connections to continue to operate.

19.1.4 How the POP Server Handles Foreign Message Formats

POP contains minimal support for mail messages that contain foreign formats. Such messages are usually binary and therefore are not transferred to the POP client. Instead, the POP server transfers the message headers, along with a brief message instructing the user to log in and extract the foreign message into a file. Foreign messages are moved into your MAIL folder; they are never deleted by the POP server.

19.1.5 How the POP Server Authorizes Users

Table 19-1 outlines the methods the POP server process uses to authorize user access.

Table 19-1 POP User Authorization Methods
Method Description
Shared secret-password string Most secure POP server access method. Initiated by the client system through the APOP command.

Allows a user to become authorized by the POP server without the need to send a password over the network. Eliminates a potential path for unauthorized users to obtain a password and break into the system.

POP requires a shared secret string from any user who wants to read mail using the APOP authorization method. For information about creating the shared secret string, see the HP TCP/IP Services for OpenVMS User's Guide.

User name and password Least secure POP server access method. Initiated by the client system through the USER and PASS commands.

The POP server authorizes the client to access the desired mailbox based on receipt of a valid user name and password.

  1. The user configures a user name and password into the POP client system. Each POP client has its own method of configuring. Note that the user name and password pair is the user name and password for the TCP/IP Services system, not for the POP client system.
  2. The POP client sends the user name and password pair to the server, and the server confirms the pair against that in the OpenVMS SYSUAF file. Note that the password is sent unencrypted over the TCP connection, which might cause security problems for some environments. Upon authorization, the POP server allows access to the user's OpenVMS mailbox.
OpenVMS SYSUAF settings on user accounts Access to the POP server is not permitted if:
  • Either the DISMAIL or DISUSER flags are set for the account.
  • The account has expired according to the SYSUAF expiration date.
  • Access has been denied because of an incorrect user name and password.
Ability to disable the USER and PASS commands Allows the system manager to use the APOP authorization method for all POP clients, the more secure means of user authorization. When you disable the USER and PASS commands (by defining the logical name TCPIP$POP_DISUSERPASS), the POP server responds to the commands with a failure message.

19.1.6 Understanding POP Message Headers

Mail message headers sent by the POP server must conform to the standard specified for SMTP in RFC 822. Because many of the messages received on an OpenVMS system are not in the SMTP format (for example, DECnet mail or mail from another message transport system), the POP server builds a new set of headers for each message based on the OpenVMS message headers.

The headers on mail messages forwarded by the POP server are as follows:
POP Message Header Obtained From
Date: Arrival date of message. Changed to UNIX format.
From: OpenVMS message From: field. Rebuilt to ensure RFC 822 compatibility. See Section
To: OpenVMS Mail To: field. Not rebuilt.
CC: OpenVMS Mail CC: field. Not rebuilt.
Subject: OpenVMS Mail Subj: field. Not rebuilt.
X-VMS-From: OpenVMS Mail From: field. Not rebuilt.
X-POP3-Server: Server host name and POP version information. Sent only if logical name TCPIP$POP_SEND_ID_HEADERS is defined.
X-POP3-ID: Message UID. Sent only if logical name TCPIP$POP_SEND_ID_HEADERS is defined.

The POP server sends these message headers to the POP client unless all of the following conditions are true:

Note that the POP server checks the SMTP configuration database to ensure that it has been configured with the qualifier /OPTION=TOP_HEADERS so that headers print at the top of the message. If the POP logical name TCPIP$POP_IGNORE_MAIL11_HEADERS is defined, the SMTP option TOP_HEADERS must also be set. If not, the POP server issues a warning in the log file and does not acknowledge the TCPIP$POP_IGNORE_MAIL11_HEADERS definition. How POP Rebuilds the OpenVMS Mail From: Field

The most important message header is the From: header, because it can be used as a destination address if a reply is requested from the POP client. Therefore, the POP server rebuilds the OpenVMS Mail From: field in compliance with RFC 822 before sending the header to the POP client.

The different types of addresses that can appear in the OpenVMS Mail From: field are as follows:
Address Type Address Format
SMTP SMTP%" legal-address," where legal-address is an address that is compliant with RFC 822 and is commonly in the user@domain format
DECnet node::username
User name username
DECnet address within quotation marks node::"user@host"
Cluster-forwarding SMTP address node::SMTP% "user@domain"

A host name is local if one of the following is true:

Some POP client systems are confused by the use of personal names when you attempt to reply to a mail message or when the name contains commas or other special characters. If you define the TCPIP$POP_PERSONAL_NAME logical name outlined in Section 19.3, make sure you test the configuration carefully with your POP client systems.

The following sections describe how POP rebuilds the message From: field for each type of address.

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