The destination is aimed at a fully controlled local, or near-local, trusted SMTP server. The goal is to send mail to trusted recipients, through a controlled channel. It hands mails over to an SMTP server, and that is all it does, therefore the resulting solution is as reliable as sending an e-mail in general. For example, syslog-ng OSE does not verify whether the recipient exists.
The smtp() driver sends e-mail messages triggered by log messages. The smtp() driver uses SMTP, without needing external applications. You can customize the main fields of the e-mail, add extra headers, send the e-mail to multiple recipients, and so on.
The subject(), body(), and header() fields may include macros which get expanded in the e-mail. For more information on available macros see Macros of syslog-ng OSE.
The smtp() driver has the following required parameters: host(), port(), from(), to(), subject(), and body(). For the list of available optional parameters, see smtp() destination options.
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NOTE:
The smtp() destination driver is available only in |
smtp(host() port() from() to() subject() body() options());
The following example defines an smtp() destination using only the required parameters.
destination d_smtp { smtp( host("localhost") port(25) from("syslog-ng alert service" "noreply@example.com") to("Admin #1" "admin1@example.com") subject("[ALERT] Important log message of $LEVEL condition received from $HOST/$PROGRAM!") body("Hi!\nThe syslog-ng alerting service detected the following important log message:\n $MSG\n-- \nsyslog-ng\n") ); };
The following example sets some optional parameters as well.
destination d_smtp { smtp( host("localhost") port(25) from("syslog-ng alert service" "noreply@example.com") to("Admin #1" "admin1@example.com") to("Admin #2" "admin2@example.com") cc("Admin BOSS" "admin.boss@example.com") bcc("Blind CC" "blindcc@example.com") subject("[ALERT] Important log message of $LEVEL condition received from $HOST/$PROGRAM!") body("Hi!\nThe syslog-ng alerting service detected the following important log message:\n $MSG\n-- \nsyslog-ng\n") header("X-Program", "$PROGRAM") ); };
The following example sends an e-mail alert if the eth0 network interface of the host is down.
filter f_linkdown { match("eth0: link down" value("MESSAGE")); }; destination d_alert { smtp( host("localhost") port(25) from("syslog-ng alert service" "syslog@localhost") reply-to("Admins" "root@localhost") to("Ennekem" "me@localhost") subject("[SYSLOG ALERT]: eth0 link down") body("Syslog received an alert:\n$MSG") ); }; log { source(s_local); filter(f_linkdown); destination(d_alert); };
The smtp() sends e-mail messages using SMTP, without needing external applications. The smtp() destination has the following options:
Type: | string |
Default: | n/a |
Description: The BODY field of the e-mail. You can also use macros in the string. Use \n to start a new line. For example:
body("syslog-ng OSE received the following alert from $HOST:\n$MSG")
Type: | string |
Default: | n/a |
Description: The BCC recipient of the e-mail (contents of the BCC field). You can specify the e-mail address, or the name and the e-mail address. Set the bcc() option multiple times to send the e-mail to multiple recipients. For example: bcc("admin@example.com") or bcc("Admin" "admin@example.com") or bcc("Admin" "admin@example.com") bcc("Admin2" "admin2@example.com")
You can also use macros to set the value of this parameter.
Type: | string |
Default: | n/a |
Description: The CC recipient of the e-mail (contents of the CC field). You can specify the e-mail address, or the name and the e-mail address. Set the cc() option multiple times to send the e-mail to multiple recipients. For example: cc("admin@example.com") or cc("Admin" "admin@example.com") or cc("Admin" "admin@example.com") cc("Admin2" "admin2@example.com")
You can also use macros to set the value of this parameter.
Description: This option enables putting outgoing messages into the disk buffer of the destination to avoid message loss in case of a system failure on the destination side. It has the following options:
reliable() | |||
Type: | yes|no | ||
Default: | no | ||
Description: If set to yes, syslog-ng OSE cannot lose logs in case of reload/restart, unreachable destination or syslog-ng OSE crash. This solution provides a slower, but reliable disk-buffer option. It is created and initialized at startup and gradually grows as new messages arrive. If set to no, the normal disk-buffer will be used. This provides a faster, but less reliable disk-buffer option.
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disk-buf-size() | |
Type: | number (bytes) |
Default: | |
Description: This is a required option. The maximum size of the disk-buffer in bytes. The minimum value is 1048576 bytes. If you set a smaller value, the minimum value will be used automatically. It replaces the old log-disk-fifo-size() option. |
mem-buf-length() | |
Type: | number (messages) |
Default: | 10000 |
Description: Use this option if the option reliable() is set to no. This option contains the number of messages stored in overflow queue. It replaces the old log-fifo-size() option. It inherits the value of the global log-fifo-size() option if provided. If it is not provided, the default value is 10000 messages. Note that this option will be ignored if the option reliable() is set to yes. |
mem-buf-size() | |
Type: | number (bytes) |
Default: | 163840000 |
Description: Use this option if the option reliable() is set to yes. This option contains the size of the messages in bytes that is used in the memory part of the disk buffer. It replaces the old log-fifo-size() option. It does not inherit the value of the global log-fifo-size() option, even if it is provided. Note that this option will be ignored if the option reliable() is set to no. |
qout-size() | |
Type: | number (messages) |
Default: | 64 |
Description: The number of messages stored in the output buffer of the destination. Note that if you change the value of this option and the disk-buffer already exists, the change will take effect when the disk-buffer becomes empty. |
Options reliable() and disk-buf-size() are required options.
In the following case reliable disk-buffer() is used.
destination d_demo { network( "127.0.0.1" port(3333) disk-buffer( mem-buf-size(10000) disk-buf-size(2000000) reliable(yes) dir("/tmp/disk-buffer") ) ); };
In the following case normal disk-buffer() is used.
destination d_demo { network( "127.0.0.1" port(3333) disk-buffer( mem-buf-length(10000) disk-buf-size(2000000) reliable(no) dir("/tmp/disk-buffer") ) ); };
Accepted values: | number [bytes] |
Default: | none |
Description: Sets the maximum size of payload in a batch. If the size of the messages reaches this value, syslog-ng OSE sends the batch to the destination even if the number of messages is less than the value of the batch-lines() option.
Note that if the batch-timeout() option is enabled and the queue becomes empty, syslog-ng OSE flushes the messages only if batch-timeout() expires, or the batch reaches the limit set in batch-bytes().
Available in syslog-ng OSE version
Type: | number |
Default: | 1 |
Description: Specifies how many lines are flushed to a destination in one batch. The syslog-ng OSE application waits for this number of lines to accumulate and sends them off in a single batch. Increasing this number increases throughput as more messages are sent in a single batch, but also increases message latency.
For example, if you set batch-lines() to 100, syslog-ng OSE waits for 100 messages.
If the batch-timeout() option is disabled, the syslog-ng OSE application flushes the messages if it has sent batch-lines() number of messages, or the queue became empty. If you stop or reload syslog-ng OSE or in case of network sources, the connection with the client is closed, syslog-ng OSE automatically sends the unsent messages to the destination.
Note that if the batch-timeout() option is enabled and the queue becomes empty, syslog-ng OSE flushes the messages only if batch-timeout() expires, or the batch reaches the limit set in batch-lines().
For optimal performance, make sure that the syslog-ng OSE source that feeds messages to this destination is configured properly: the value of the log-iw-size() option of the source must be higher than the batch-lines()*workers() of the destination. Otherwise, the size of the batches cannot reach the batch-lines() limit.
Type: | time in milliseconds |
Default: | -1 (disabled) |
Description: Specifies the time syslog-ng OSE waits for lines to accumulate in the output buffer. The syslog-ng OSE application sends batches to the destinations evenly. The timer starts when the first message arrives to the buffer, so if only few messages arrive, syslog-ng OSE sends messages to the destination at most once every batch-timeout() milliseconds.
Type: | string |
Default: | n/a |
Description: The sender of the e-mail (contents of the FROM field). You can specify the e-mail address, or the name and the e-mail address. For example:
from("admin@example.com")or
from("Admin" "admin@example.com")
If you specify the from() option multiple times, the last value will be used. Instead of the from() option, you can also use sender(), which is just an alias of the from() option.
You can also use macros to set the value of this parameter.
Type: | string |
Default: | n/a |
Description: Adds an extra header to the e-mail with the specified name and content. The first parameter sets the name of the header, the second one its value. The value of the header can contain macros. Set the header() option multiple times to add multiple headers. For example:
header("X-Program", "$PROGRAM")
When using the header option, note the following points:
Do not use the header() option to set the values of headers that have dedicated options. Use it only to add extra headers.
If you set the same custom header multiple times, only the first will be added to the e-mail, other occurrences will be ignored.
It is not possible to set the DATE, Return-Path, Original-Recipient, Content-*, MIME-*, Resent-*, Received headers.
Description: This option makes it possible to execute external programs when the relevant driver is initialized or torn down. The hook-commands() can be used with all source and destination drivers with the exception of the usertty() and internal() drivers.
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NOTE: The syslog-ng OSE application must be able to start and restart the external program, and have the necessary permissions to do so. For example, if your host is running AppArmor or SELinux, you might have to modify your AppArmor or SELinux configuration to enable syslog-ng OSE to execute external applications. |
To execute an external program when syslog-ng OSE starts or stops, use the following options:
startup() | |
Type: | string |
Default: | N/A |
Description: Defines the external program that is executed as syslog-ng OSE starts. |
shutdown() | |
Type: | string |
Default: | N/A |
Description: Defines the external program that is executed as syslog-ng OSE stops. |
To execute an external program when the syslog-ng OSE configuration is initiated or torn down, for example, on startup/shutdown or during a syslog-ng OSE reload, use the following options:
setup() | |
Type: | string |
Default: | N/A |
Description: Defines an external program that is executed when the syslog-ng OSE configuration is initiated, for example, on startup or during a syslog-ng OSE reload. |
teardown() | |
Type: | string |
Default: | N/A |
Description: Defines an external program that is executed when the syslog-ng OSE configuration is stopped or torn down, for example, on shutdown or during a syslog-ng OSE reload. |
In the following example, the hook-commands() is used with the network() driver and it opens an iptables port automatically as syslog-ng OSE is started/stopped.
The assumption in this example is that the LOGCHAIN chain is part of a larger ruleset that routes traffic to it. Whenever the syslog-ng OSE created rule is there, packets can flow, otherwise the port is closed.
source { network(transport(udp) hook-commands( startup("iptables -I LOGCHAIN 1 -p udp --dport 514 -j ACCEPT") shutdown("iptables -D LOGCHAIN 1") ) ); };
Type: | hostname or IP address |
Default: | n/a |
Description: Hostname or IP address of the SMTP server.
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NOTE:
If you specify host="localhost", syslog-ng OSE will use a socket to connect to the local SMTP server. Use host="127.0.0.1" to force TCP communication between syslog-ng OSE and the local SMTP server. |
Type: | number |
Default: | Use global setting. |
Description: The number of messages that the output queue can store.
Type: | number |
Default: | 25 |
Description: The port number of the SMTP server.
Type: | string |
Default: | n/a |
Description: Replies of the recipient will be sent to this address (contents of the REPLY-TO field). You can specify the e-mail address, or the name and the e-mail address. Set the reply-to() option multiple times to send the e-mail to multiple recipients. For example: reply-to("admin@example.com") or reply-to("Admin" "admin@example.com") or reply-to("Admin" "admin@example.com") reply-to("Admin2" "admin2@example.com")
You can also use macros to set the value of this parameter.
Type: | number (of attempts) |
Default: | 3 |
Description: The number of times syslog-ng OSE attempts to send a message to this destination. If syslog-ng OSE could not send a message, it will try again until the number of attempts reaches retries, then drops the message.
Type: | string |
Default: | n/a |
Description: The SUBJECT field of the e-mail. You can also use macros. For example:
subject("[SYSLOG ALERT]: Critical error message received from $HOST")
If you specify the subject() option multiple times, the last value will be used.
Type: | number |
Default: | 0 |
Description: Sets the maximum number of messages sent to the destination per second. Use this output-rate-limiting functionality only when using disk-buffer as well to avoid the risk of losing messages. Specifying 0 or a lower value sets the output limit to unlimited.
Type: | string |
Default: | localhost |
Description: The recipient of the e-mail (contents of the TO field). You can specify the e-mail address, or the name and the e-mail address. Set the to() option multiple times to send the e-mail to multiple recipients. For example: to("admin@example.com") or to("Admin" "admin@example.com") or to("Admin" "admin@example.com") to("Admin2" "admin2@example.com")
You can also use macros to set the value of this parameter.
The snmp() driver sends SNMP traps using the Simple Network Management Protocol version 2c or version 3. Incoming log messages can be converted to SNMP traps, as the fields of the SNMP messages can be customized using syslog-ng OSE macros.
The snmp() driver is available in syslog-ng OSE version
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NOTE:
The snmp destination driver currently supports sending SNMP traps only using the UDP transport protocol. |
The snmp() driver requires the host(), trap-obj(), and snmp-obj() options to be set, as well as the engine-id() and version() options when using the SNMPv3 protocol. For the list of available optional parameters, see snmp() destination options.
destination d_snmp {snmp(host() trap-obj() snmp-obj() ...);};
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Caution:
If syslog-ng OSE cannot resolve the destination hostname during startup, it will try to resolve the hostname again when the next message to be sent as an SNMP trap is received. However, if this name resolution fails, the trap will be dropped. |
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NOTE:
The snmp() destination driver does not generate MARK signals itself, but can receive and forward MARK signals. |
The following example defines an SNMP destination that uses the SNMPv2c protocol.
destination d_snmpv2c{ snmp( version('v2c') host('192.168.1.1') trap-obj('.1.3.6.1.6.3.1.1.4.1.0', 'Objectid', '.1.3.6.1.4.1.18372.3.1.1.1.2.1') snmp-obj('.1.3.6.1.4.1.18372.3.1.1.1.1.1.0', 'Octetstring', 'Test SNMP trap') snmp-obj('.1.3.6.1.4.1.18372.3.1.1.1.1.2.0', 'Octetstring', 'admin') snmp-obj('.1.3.6.1.4.1.18372.3.1.1.1.1.3.0', 'Ipaddress', '192.168.1.1') ); };
The following example defines an SNMP destination that uses the SNMPv3 protocol and uses macros to fill the values of the SNMP objects.
destination d_snmpv3{ snmp( version('v3') host('192.168.1.1') port(162) engine-id('0xdeadbeefde') auth-username('myusername') auth-password('password') enc-algorithm('AES') enc-password('password') trap-obj('.1.3.6.1.6.3.1.1.4.1.0', 'Objectid', '.1.3.6.1.4.1.18372.3.1.1.1.2.1') snmp-obj('.1.3.6.1.4.1.18372.3.1.1.1.1.1', 'Octetstring', '${MESSAGE}') snmp-obj('.1.3.6.1.4.1.18372.3.1.1.1.1.2', 'Octetstring', 'admin') snmp-obj('.1.3.6.1.4.1.18372.3.1.1.1.1.3', 'Ipaddress', '${SOURCEIP}') ); };
The syslog-ng OSE application can convert the syslog messages sent by Cisco devices to Cisco-specific SNMP traps defined by the CISCO-SYSLOG-MIB (enterprises.cisco.ciscoMgmt.ciscoCiscoMIB) is also supported (such traps are also referred to as clogMessageGenerated notifications). That way, the incoming log messages can be forwarded to devices used to process and analyze Cisco-specific SNMP traps. For this to work correctly, the following requirements must be met:
The syslog-ng Source Configuration Library (SCL) must be included in the syslog-ng OSE configuration file:
@include "scl.conf"
The pattern database described in Parsing Cisco-specific message fields with patterndb must be used to parse the incoming log messages.
To accomplish this, syslog-ng OSE has to use a special pattern database to parse the Cisco-specific syslog messages, because these messages do not comply with the standard syslog formats.
For details on the Cisco-specific SNMP trap format, see CISCO-SYSLOG-MIB on the Cisco website.
The ${PROGRAM} part of the syslog messages sent by Cisco devices contain not only the program name, but other important protocol information part as well. The ${PROGRAM} of these messages contains the Facility, Severity, and the Mnemonic (the Cisco name) of the message. The following pattern database parses these values and makes them available as the .cisco.Facility, .cisco.Severity, and .cisco.MsgName, respectively. The actual log message is available as .cisco.MsgText.
<patterndb version="4" pub_date="2011-05-03"> <ruleset name="cisco snmp ruleset1" xml:id="480de478-d4a6-4a7f-bea4-0c0245d361e3"> <description>Pattern for Cisco messages having BSD timestamps, for example: Jul 01 2010 00:32:59: %SYS-5-CONFIG_I: Configured from console by console</description> <pattern>%@ESTRING:.cisco.Facility:-@@ESTRING:.cisco.Severity:-@@ANYSTRING:.cisco.MsgName@</pattern> <rules> <rule xml:id="09944c71-95eb-4bc0-8575-936931d85713" provider="oneidentity" class="system"> <patterns> <pattern> @ANYSTRING:.cisco.MsgText@</pattern> </patterns> </rule> </rules> </ruleset> <ruleset name="cisco snmp ruleset2" xml:id="480de478-d4a6-4a7f-bea4-0c0245d361e3"> <description>Pattern for Cisco messages having cisco-specific timestamps, for example: 18: Jan 22 10:45:44.543: %SYS-5-CONFIG_I: Configured from console by console</description> <rules> <rule xml:id="09944c71-95eb-4bc0-8575-936931d85714" provider="oneidentity" class="system"> <patterns> <pattern>%@ESTRING:.cisco.Facility:-@@ESTRING:.cisco.Severity:-@@ESTRING:.cisco.MsgName::@ @ANYSTRING:.cisco.MsgText@</pattern> </patterns> </rule> </rules> </ruleset> </patterndb>
To send out clogMessageGenerated SNMP traps, use the cisco_snmp() destination driver. The cisco-snmp() destination is actually a modified version of the snmp() destination driver.
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NOTE:
The cisco-snmp() driver is actually a reusable configuration snippet. For details on using or writing SCLs, see Reusing configuration blocks. |
The cisco-snmp() driver has the same requirements and options as the snmp() destination driver, but automatically fills the clogMessageGenerated-specific fields with the data received from parsing the Cisco-specific syslog messages using the pattern database. For details on the , see the <INSTALLDIR>/ share/include/scl/snmp/plugin.conf file.
Declaration:
destination d_cisco_snmp {cisco-snmp(host(<hostname>));};
The following example defines an SNMP destination that sends out clogMessageGenerated messages using the SNMPv3 protocol.
destination d_cisco_snmp {cisco-snmp(host("192.168.1.1") version("v3") engine-id("'0xdeadbeefde'") auth-username('myusername') auth-password('password') enc-password('password'));};
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