NSCAServer

A server that listens for incoming NSCA connection and processes incoming requests.

Enable module

To enable this module and and allow using the commands you need to ass NSCAServer = enabled to the [/modules] section in nsclient.ini:

[/modules]
NSCAServer = enabled

Configuration

Path / Section	Description
/settings/NSCA/server	NSCA SERVER SECTION
/settings/default	Default values

NSCA SERVER SECTION

Section for NSCA (NSCAServer) (check_nsca) protocol options.

Key	Default Value	Description
allowed ciphers	ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH	ALLOWED CIPHERS
allowed hosts	127.0.0.1	Allowed hosts
bind to		BIND TO ADDRESS
ca	${certificate-path}/ca.pem	CA
cache allowed hosts	true	Cache list of allowed hosts
certificate	${certificate-path}/certificate.pem	SSL CERTIFICATE
certificate format	PEM	CERTIFICATE FORMAT
certificate key		SSL CERTIFICATE
debug verify	false	Debug peer certificate verification
dh		DH KEY
encryption	aes256	ENCRYPTION
inbox	inbox	INBOX
password		Password
payload length	512	PAYLOAD LENGTH
performance data	true	PERFORMANCE DATA
port	5667	PORT NUMBER
socket queue size	0	LISTEN QUEUE
ssl options		VERIFY MODE
thread pool	10	THREAD POOL
timeout	30	TIMEOUT
timezone	utc	TIMEZONE
tls version	tlsv1.2+	TLS version to use
use ssl	false	ENABLE SSL ENCRYPTION
verify mode	none	VERIFY MODE

# Section for NSCA (NSCAServer) (check_nsca) protocol options.
[/settings/NSCA/server]
allowed ciphers=ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH
allowed hosts=127.0.0.1
ca=${certificate-path}/ca.pem
cache allowed hosts=true
certificate=${certificate-path}/certificate.pem
certificate format=PEM
debug verify=false
encryption=aes256
inbox=inbox
payload length=512
performance data=true
port=5667
socket queue size=0
thread pool=10
timeout=30
timezone=utc
tls version=tlsv1.2+
use ssl=false
verify mode=none

ALLOWED CIPHERS

The chipers which are allowed to be used. The default here will differ is used in “insecure” mode or not. check_nrpe uses a very old chipers and should preferably not be used. For details of chipers please see the OPEN ssl documentation: https://www.openssl.org/docs/apps/ciphers.html

Key	Description
Path:	/settings/NSCA/server
Key:	allowed ciphers
Advanced:	Yes (means it is not commonly used)
Default value:	ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH

Sample:

[/settings/NSCA/server]
# ALLOWED CIPHERS
allowed ciphers=ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH

Allowed hosts

A comma separated list of allowed hosts. You can use netmasks (/ syntax) or * to create ranges.

Key	Description
Path:	/settings/NSCA/server
Key:	allowed hosts
Default value:	127.0.0.1

Sample:

[/settings/NSCA/server]
# Allowed hosts
allowed hosts=127.0.0.1

BIND TO ADDRESS

Allows you to bind server to a specific local address. This has to be a dotted ip address not a host name. Leaving this blank will bind to all available IP addresses.

Key	Description
Path:	/settings/NSCA/server
Key:	bind to
Default value:	N/A

Sample:

[/settings/NSCA/server]
# BIND TO ADDRESS
bind to=

CA

Key	Description
Path:	/settings/NSCA/server
Key:	ca
Advanced:	Yes (means it is not commonly used)
Default value:	${certificate-path}/ca.pem

Sample:

[/settings/NSCA/server]
# CA
ca=${certificate-path}/ca.pem

Cache list of allowed hosts

If host names (DNS entries) should be cached, improves speed and security somewhat but won’t allow you to have dynamic IPs for your Nagios server.

Key	Description
Path:	/settings/NSCA/server
Key:	cache allowed hosts
Default value:	true

Sample:

[/settings/NSCA/server]
# Cache list of allowed hosts
cache allowed hosts=true

SSL CERTIFICATE

Key	Description
Path:	/settings/NSCA/server
Key:	certificate
Advanced:	Yes (means it is not commonly used)
Default value:	${certificate-path}/certificate.pem

Sample:

[/settings/NSCA/server]
# SSL CERTIFICATE
certificate=${certificate-path}/certificate.pem

CERTIFICATE FORMAT

Key	Description
Path:	/settings/NSCA/server
Key:	certificate format
Advanced:	Yes (means it is not commonly used)
Default value:	PEM

Sample:

[/settings/NSCA/server]
# CERTIFICATE FORMAT
certificate format=PEM

SSL CERTIFICATE

Key	Description
Path:	/settings/NSCA/server
Key:	certificate key
Advanced:	Yes (means it is not commonly used)
Default value:	N/A

Sample:

[/settings/NSCA/server]
# SSL CERTIFICATE
certificate key=

Debug peer certificate verification

Set this to tru to output certificate verification errors, these are outputed to stdout (not the log).

Key	Description
Path:	/settings/NSCA/server
Key:	debug verify
Advanced:	Yes (means it is not commonly used)
Default value:	false

Sample:

[/settings/NSCA/server]
# Debug peer certificate verification
debug verify=false

DH KEY

Key	Description
Path:	/settings/NSCA/server
Key:	dh
Advanced:	Yes (means it is not commonly used)
Default value:	N/A

Sample:

[/settings/NSCA/server]
# DH KEY
dh=

ENCRYPTION

Name of encryption algorithm to use. Has to be the same as your agent i using or it wont work at all.This is also independent of SSL and generally used instead of SSL. Available encryption algorithms are: none = No Encryption (not safe) xor = XOR des = DES 3des = DES-EDE3 cast128 = CAST-128 xtea = XTEA blowfish = Blowfish twofish = Twofish rc2 = RC2 aes128 = AES aes192 = AES aes = AES serpent = Serpent gost = GOST

Key	Description
Path:	/settings/NSCA/server
Key:	encryption
Default value:	aes256

Sample:

[/settings/NSCA/server]
# ENCRYPTION
encryption=aes256

INBOX

The default channel to post incoming messages on

Key	Description
Path:	/settings/NSCA/server
Key:	inbox
Default value:	inbox

Sample:

[/settings/NSCA/server]
# INBOX
inbox=inbox

Password

Password used to authenticate against server

Key	Description
Path:	/settings/NSCA/server
Key:	password
Default value:	N/A

Sample:

[/settings/NSCA/server]
# Password
password=

PAYLOAD LENGTH

Length of payload to/from the NSCA agent. This is a hard specific value so you have to “configure” (read recompile) your NSCA agent to use the same value for it to work.

Key	Description
Path:	/settings/NSCA/server
Key:	payload length
Default value:	512

Sample:

[/settings/NSCA/server]
# PAYLOAD LENGTH
payload length=512

PERFORMANCE DATA

Send performance data back to nagios (set this to false to remove all performance data).

Key	Description
Path:	/settings/NSCA/server
Key:	performance data
Default value:	true

Sample:

[/settings/NSCA/server]
# PERFORMANCE DATA
performance data=true

PORT NUMBER

Port to use for NSCA.

Key	Description
Path:	/settings/NSCA/server
Key:	port
Default value:	5667

Sample:

[/settings/NSCA/server]
# PORT NUMBER
port=5667

LISTEN QUEUE

Number of sockets to queue before starting to refuse new incoming connections. This can be used to tweak the amount of simultaneous sockets that the server accepts.

Key	Description
Path:	/settings/NSCA/server
Key:	socket queue size
Advanced:	Yes (means it is not commonly used)
Default value:	0

Sample:

[/settings/NSCA/server]
# LISTEN QUEUE
socket queue size=0

VERIFY MODE

Comma separated list of verification flags to set on the SSL socket.

default-workarounds Various workarounds for what I understand to be broken ssl implementations no-sslv2 Do not use the SSLv2 protocol (prefer tls version instead). no-sslv3 Do not use the SSLv3 protocol (prefer tls version instead). no-tlsv1 Do not use the TLSv1 protocol (prefer tls version instead). no-tlsv1_1 Do not use the TLSv1.1 protocol (prefer tls version instead). no-tlsv1_2 Do not use the TLSv1.2 protocol (prefer tls version instead). no-tlsv1_3 Do not use the TLSv1.3 protocol (prefer tls version instead). single-dh-use Always create a new key when using temporary/ephemeral DH parameters. This option must be used to prevent small subgroup attacks, when the DH parameters were not generated using “strong” primes (e.g. when using DSA-parameters).

Key	Description
Path:	/settings/NSCA/server
Key:	ssl options
Advanced:	Yes (means it is not commonly used)
Default value:	N/A

Sample:

[/settings/NSCA/server]
# VERIFY MODE
ssl options=

THREAD POOL

Key	Description
Path:	/settings/NSCA/server
Key:	thread pool
Advanced:	Yes (means it is not commonly used)
Default value:	10

Sample:

[/settings/NSCA/server]
# THREAD POOL
thread pool=10

TIMEOUT

Timeout (in seconds) when reading packets on incoming sockets. If the data has not arrived within this time we will bail out.

Key	Description
Path:	/settings/NSCA/server
Key:	timeout
Default value:	30

Sample:

[/settings/NSCA/server]
# TIMEOUT
timeout=30

TIMEZONE

Reference timezone for the wire timestamp emitted in the IV packet and used by the replay-window check. The protocol specification calls for UTC (default). Set to ‘local’ (or any POSIX TZ string) only when interoperating with a legacy agent that wrote local-clock-as-Unix-time into the wire field. Both ends must agree on the value.

Key	Description
Path:	/settings/NSCA/server
Key:	timezone
Default value:	utc

Sample:

[/settings/NSCA/server]
# TIMEZONE
timezone=utc

TLS version to use

Valid options are tlsv1.3, tlsv1.2, tlsv1.1, tlsv1.0, sslv3 as well as tlsv1.3+, tlsv1.2+, tlsv1.1+, tlsv1.0+, sslv3+ (Which uses the version mentioned and above)

Key	Description
Path:	/settings/NSCA/server
Key:	tls version
Advanced:	Yes (means it is not commonly used)
Default value:	tlsv1.2+

Sample:

[/settings/NSCA/server]
# TLS version to use
tls version=tlsv1.2+

ENABLE SSL ENCRYPTION

This option controls if SSL should be enabled.

Key	Description
Path:	/settings/NSCA/server
Key:	use ssl
Default value:	false

Sample:

[/settings/NSCA/server]
# ENABLE SSL ENCRYPTION
use ssl=false

VERIFY MODE

Comma separated list of verification flags to set on the SSL socket.

none The server will not send a client certificate request to the client, so the client will not send a certificate. peer The server sends a client certificate request to the client and the certificate returned (if any) is checked. fail-if-no-cert if the client did not return a certificate, the TLS/SSL handshake is immediately terminated. This flag must be used together with peer. peer-cert Alias for peer and fail-if-no-cert. workarounds Various bug workarounds. single Always create a new key when using tmp_dh parameters. client-once Only request a client certificate on the initial TLS/SSL handshake. This flag must be used together with verify-peer

Key	Description
Path:	/settings/NSCA/server
Key:	verify mode
Advanced:	Yes (means it is not commonly used)
Default value:	none

Sample:

[/settings/NSCA/server]
# VERIFY MODE
verify mode=none

Default values

Default values used in other config sections.

Key	Default Value	Description
allowed hosts	127.0.0.1	Allowed hosts
bind to		BIND TO ADDRESS
cache allowed hosts	true	Cache list of allowed hosts
encoding		NRPE PAYLOAD ENCODING
inbox	inbox	INBOX
password		Password
socket queue size	0	LISTEN QUEUE
thread pool	10	THREAD POOL
timeout	30	TIMEOUT
timezone	local	Timezone

# Default values used in other config sections.
[/settings/default]
allowed hosts=127.0.0.1
cache allowed hosts=true
inbox=inbox
socket queue size=0
thread pool=10
timeout=30
timezone=local

Allowed hosts

A comma separated list of allowed hosts. You can use netmasks (/ syntax) or * to create ranges.

Key	Description
Path:	/settings/default
Key:	allowed hosts
Default value:	127.0.0.1

Sample:

[/settings/default]
# Allowed hosts
allowed hosts=127.0.0.1

BIND TO ADDRESS

Allows you to bind server to a specific local address. This has to be a dotted ip address not a host name. Leaving this blank will bind to all available IP addresses.

Key	Description
Path:	/settings/default
Key:	bind to
Default value:	N/A

Sample:

[/settings/default]
# BIND TO ADDRESS
bind to=

Cache list of allowed hosts

If host names (DNS entries) should be cached, improves speed and security somewhat but won’t allow you to have dynamic IPs for your Nagios server.

Key	Description
Path:	/settings/default
Key:	cache allowed hosts
Default value:	true

Sample:

[/settings/default]
# Cache list of allowed hosts
cache allowed hosts=true

NRPE PAYLOAD ENCODING

Key	Description
Path:	/settings/default
Key:	encoding
Advanced:	Yes (means it is not commonly used)
Default value:	N/A

Sample:

[/settings/default]
# NRPE PAYLOAD ENCODING
encoding=

INBOX

The default channel to post incoming messages on

Key	Description
Path:	/settings/default
Key:	inbox
Default value:	inbox

Sample:

[/settings/default]
# INBOX
inbox=inbox

Password

Password used to authenticate against server

Key	Description
Path:	/settings/default
Key:	password
Default value:	N/A

Sample:

[/settings/default]
# Password
password=

LISTEN QUEUE

Number of sockets to queue before starting to refuse new incoming connections. This can be used to tweak the amount of simultaneous sockets that the server accepts.

Key	Description
Path:	/settings/default
Key:	socket queue size
Advanced:	Yes (means it is not commonly used)
Default value:	0

Sample:

[/settings/default]
# LISTEN QUEUE
socket queue size=0

THREAD POOL

Key	Description
Path:	/settings/default
Key:	thread pool
Advanced:	Yes (means it is not commonly used)
Default value:	10

Sample:

[/settings/default]
# THREAD POOL
thread pool=10

TIMEOUT

Timeout (in seconds) when reading packets on incoming sockets. If the data has not arrived within this time we will bail out.

Key	Description
Path:	/settings/default
Key:	timeout
Default value:	30

Sample:

[/settings/default]
# TIMEOUT
timeout=30

Timezone

Timezone used to render dates such as boot time. Accepts ‘local’ (default), ‘utc’, or any POSIX TZ string parseable by Boost.Date_time (e.g. ‘MST-07’ or ‘EST-05EDT,M3.2.0,M11.1.0’).

Key	Description
Path:	/settings/default
Key:	timezone
Advanced:	Yes (means it is not commonly used)
Default value:	local

Sample:

[/settings/default]
# Timezone
timezone=local