Use
the TargetServer statement to specify one or more target servers (resolved
or configured IP addresses) and their connection attributes. CSSMTP
establishes connections to the target servers in order to send mail.
Rules: - If you are configuring the TargetIP parameter, the TargetName
parameter, or both, then you can configure multiple TargetServer statements.
- When you issue a MODIFY REFRESH command, if the order of the target
servers changes, the configuration is updated.
- Each TargetIP or TargetName must be unique.
Results: - Only the first four unique TargetIP values, TargetName values,
or both values are used. If more than four values are configured,
the application issues a console message and logs a warning. The four
target servers that are selected are based on the configuration order
in which the parameters were configured. CSSMTP only uses the first
four IP addresses.
- If duplicate target server IP addresses are resolved from the
configured TargetIP or from the TargetName IP addresses, CSSMTP issues
a console message and logs a warning.
- If the TCP/IP stack supports only IPv4, any configured IPv6 addresses
are ignored and the application issues a console message and logs
a warning.
Restrictions: - You must define at least one TargetServer statement, and it must
contain at least one TargetIP, TargetName, or TargetMx parameter.
- Only four TargetServer statements or the first four TargetIP and
TargetName parameters with TargetServer statements are used.
- If distinct target servers can be reached by way of a single IP
address, the target servers must have the same capabilities. For example,
if a dynamic VIPA (DVIPA) address is specified, the mail servers for
that DVIPA address must have the same capabilities. In this example,
all the servers must be ESMTPs or SMTPs, but not both, that have the
same capabilities.
- You can configure only one TargetMx parameter.
Syntax
>>-TargetServer--| Put Braces and Parameters on Separate Lines |-><
Put Braces and Parameters on Separate Lines
|--+-{---------------------------+------------------------------|
+-| TargetServer Parameters |-+
'-}---------------------------'
TargetServer Parameters
.---------------------.
V |
|----+-----------------+-+--+-----------------+----------------->
+-TargetIP addr---+ '-TargetMx mxName-'
'-TargetName name-'
.-ConnectPort 25---. .-ConnectLimit 5-----.
>--+------------------+--+--------------------+----------------->
'-ConnectPort port-' '-ConnectLimit count-'
.-MaxMsgSent 0-----. .-MessageSize 524288-.
>--+------------------+--+--------------------+----------------->
'-MaxMsgSent count-' '-MessageSize size---'
.-Secure NO------.
>--+----------------+-------------------------------------------|
'-Secure-+-NO--+-'
'-YES-'
Parameters
- ConnectPort
- Defines the port that CSSMTP uses to connect to a target server.
Result: If
an update to the port is detected during a dynamic refresh, then CSSMTP
must terminate all the active connections to the target servers that
are associated with this TargetServer statement in order to use the
new port value.
Requirement: This port must match the
listening port number used by the target server.
The valid
range of port values is 1 - 65535. The default port is 25.
- ConnectLimit
- Limits the number of concurrent socket connections to the target
server from CSSMTP. This might be useful if your server has a concurrent
connection limit. One of the socket connections is used by CSSMTP
to monitor the SMTP server.
The valid values are in the range 2
- 5. The default limit is 5 connections.
Result: If
an update to the ConnectLimit value is detected during a dynamic refresh,
CSSMTP must terminate all the active connections to the target servers
that are associated with this TargetServer statement in order to use
the new limit.
- MaxMsgSent
- Specifies the maximum number of mail messages that can be sent
on a single connection. When the MaxMsgSent value is exceeded, CSSMTP
closes the connection to the target server and reestablishes a new
connection to the same target server. Mail messages continue to be
sent over the new connection until the MaxMsgSent value is reached
again.
The valid range is 0 - 2147483647. The default is 0, which
means that an unlimited number of messages can be sent.
- MessageSize
- Specifies the maximum size of a mail message that can be sent
to target servers that do not support ESMTP size extensions.
Valid
values are in the range 1000 - 2147483647. The default size is 524288
bytes (512 KB).
- Secure
- Indicates whether Transport Layer Security (TLS) is required between
the client and a target server. TLS provides private, authenticated
communication over the internet. See the steps for setting up security for CSSMTP in z/OS Communications Server: IP Configuration
Guide.
Result: If an update to the secure
value is detected during a dynamic refresh, CSSMTP must terminate
all the active connections to the target servers that are associated
with this TargetServer statement in order to use the new secure value.
- NO
- TLS is not required between CSSMTP and a target server. However,
if the STARTTLS SMTP command is used in the spool file, a TLS connection
is attempted with this server.
- YES
- TLS is required between CSSMTP application and a target server.
If a TLS session cannot be established, then the server is not usable.
- TargetIP
- The IPv4 or IPv6 address of the target server to which CSSMTP
connects.
Restrictions: - IPv4-mapped IPv6 addresses and IPv6 addresses with the reserved
prefix ::/96 are not valid.
- The IPv6 unspecified address (::0) and IPv4 unspecified address
(0.0.0.0) are not allowed.
- Duplicate IP addresses are not allowed.
- TargetName
- The host name or fully qualified host name used for a resolver
A or AAAA query. Valid values are 1 - 255 characters in length. If
the host name is used, the resolver appends the domain information,
which is obtained from the TCPIP.DATA data set.
The TargetName
value is not case sensitive.
Result: CSSMTP only uses
the first four configured or resolved IP addresses to send the mail
message. If more than four target servers are found, this application
issues a console message and logs a warning.
Restriction: Duplicate
host names are not allowed.
- TargetMx
- The name or a fully-qualified domain name used for a resolver
MX query. This name might resolve into multiple MX records that include
a preference value. The lower the preference value is, the more likely
that the record is used. Valid values are 1 - 255 characters in length.
The
lower the value, the higher the preference.
The TargetMx value
is not case sensitive.
Results: - Only the first configured TargetMx value is used. If more than
one value is configured, the application issues a console message
and logs a warning.
- Only the first four target servers are saved for the configured
TargetMx value. If more than four target servers are returned, CSSMTP
issues a console message and logs a warning.
- The lower preference is honored by not sending mail messages to
those IP addresses unless the higher preference target servers are
unavailable.
Restriction: The TargetMx parameter is mutually
exclusive with the TargetName parameter and the TargetIP parameter.
If you want to use this statement, MX records for this TargetMx value
must exist in the DNS database. If no MX records are found then this
is handled as an error and console message EZD1815E is generated.