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Documentation - Services

Services specify actual things to monitor. The very purpose of this software. So, you'll probably need to know about them

In the config file, Services are specified as:

	Service NAME {
		data...
	}

Often, there will be no need to specify any data, and you may shorten the specification to just

	Service NAME
If you are just starting out with argus, it is recommended that you stick to the short form when possible and let argus fill in the default values. In most cases, you will only say:
    Service Ping
    Service TCP/SMTP
    Service TCP/IMAP
in your config file, and argus will default the rest.

NAME specifies the type of test. There are 4 main types of tests:

  • Ping - Pings a host
  • Prog - runs a program
  • TCP - tests a TCP port
  • UDP - tests a UDP port

Both TCP and UDP have a number of application tests built-in. Specifying an application does the same thing as setting the various bits of data to values appropriate for the protocol. But you could just as easily specify them directly.

The currently built-in application tests are:

  • TCP/SMTP TCP/FTP TCP/NNTP TCP/HTTP TCP/HTTPS TCP/Gopher TCP/Telnet TCP/SSH TCP/POP TCP/IMAP TCP/DNS TCP/LPD TCP/Whois TCP/Rwhois TCP/NFS TCP/NFSv3 TCP/POPS TCP/IMAPS TCP/SMTPS TCP/NNTPS TCP/SIP[6] TCP/Slimserver
  • UDP/SNMP UDP/SNMPv2c[7] UDP/SNMPv3[5] UDP/DNS UDP/DNSQ[1] UDP/NTP UDP/Portmap UDP/NFS UDP/NFSv3[2] UDP/RADIUS[3] UDP/SIP[6] UDP/IAX2[6]
  • several "special" tests: TCP/URL UDP/Domain TCP/RPC[6] UDP/RPC[6]

Common Data that applies to all Services

	Service NAME {
		frequency:	60
		retries:	5
		timeout:	10
	}

These do not need to be specified, they will happily default, or propagate from an enclosing group

  • frequency specifies how often the service is tested, in seconds.
    The author is aware that technically, this should be called period -- deal with it.

  • retries if a test fails, we will retry it the specified number of times before declaring it down

  • timeout how long to wait for something (eg. a response from a mail server) before giving up and declaring the test a failure.

Note, specifying that things happen every 60 seconds (for example) does not mean that they will happen at the top of every minute (:00 seconds). Argus is smart and will load balance the tests to prevent the 59 seconds of quiet followed by an intense flurry of network congestion common in some other network monitoring applications. In argus-speak, things have a frequency and a phase, called phi. You cannot set this, but it is visible in the debugging web page.

Data for Prog Tests

	Service Prog {
		# make sure no one deleted root from the passwd file
		command:	cat /etc/passwd
		expect:		^root:
	}

These need to be specified. They will not default, or propagate from anywhere

  • command the command to run, along with any commandline arguments. specify it just as you would to your shell. you should either specify a complete path to the program, or verify that it is in argus's PATH

  • expect a regular expression that needs to match the output from the command. if not specified, the exit code from the program will be used to determine success or failure

Data for Ping Tests

	Service Ping {
		hostname:	host1.example.com
	}

This needs to be specified, but will propagate from an enclosing group

hostname the hostname or IP address to ping

Data for TCP and UDP Tests

	Service TCP {
		hostname:	www.example.com
		port:		80
		send:		HEAD / HTTP/1.0\r\n\r\n
		expect:		HTTP
		readhow:	toeof
	}

Both TCP and UDP have many of the same parameters

  • hostname the hostname or IP address to test. This needs to be specified, but will propagate from an enclosing group

  • port the port to test. This needs to be specified.

  • send data to send once connected. This needs to be specified. If nothing is specified, nothing will be sent to the remote server

  • expect a regular expression that needs to match the data received from the remote server. This needs to be specified. If nothing is specified, success or failure is determined by whether or not we received any data at all

  • readhow This needs to be specified. How much data should we try to read? toeof indicates read until the remote end closes the connection. banner indicates we only want to read a banner. once indicates to use whatever data is returned in the first read(). This parameter only applies to TCP not UDP

Specifying an application (eg. TCP/SMTP) will fill in port, send, expect, and readhow as appropriate for that protocol

See below for details on the special TCP/URL, UDP/Domain, and UDP/SNMP tests

SNMP Tests

	Service UDP/SNMP {
		hostname:	cisco-1.example.com
		community:	qwerty
		oid:		.1.3.6.1.4.1.9.9.13.1.3.1.3.1
		maxvalue:	27
	}
  • hostname the hostname or IP address to test. This needs to be specified, but will propagate from an enclosing group

  • community the SNMP community. This needs to be specified, but will propagate from an enclosing group

  • oid the OID to query. It should be numeric, and the leading '.' is optional. This needs to be specified.

  • maxvalue the maximum permitted value, if the query returns something larger, we consider the service down. You can specify any of:

    • maxvalue
    • minvalue
    • eqvalue
    • nevalue

SNMPv3 Tests[5]

	Service UDP/SNMPv3 {
		hostname:	cisco-1.example.com
		oid:		.1.3.6.1.4.1.9.9.13.1.3.1.3.1
		snmpuser:	joe
		snmppass:	secret
		snmpauth:	MD5
		snmpprivpass:	supersecret
		snmppriv:	DES
		contextname:	public
		contextengine:	80000000123456
		authengine:	80000000123456
	}
  • snmpuser the snmp username This needs to be specified, but will propagate from an enclosing group

  • snmppass the snmp authentication password This needs to be specified if authentication is required, but will propagate from an enclosing group

  • snmpauth the authentication algorithm, MD5, SHA1, or none. This will default to MD5 if a password is provided, otherwise none.

  • snmpprivpass the privacy password This needs to be specified if privacy is required, but will propagate from an enclosing group

  • snmppriv the privacy encryption algorithm, DES or none. This will default to DES if a snmpprivpass is specified, otherwise none.

  • contextname the context name This needs to be specified, but will propagate from an enclosing group

  • contextengine the context engine-id This needs to be specified, but will propagate from an enclosing group, or will attempt to be auto-discovered.

  • authengine the authentication engine-id This needs to be specified, but will propagate from an enclosing group, or will attempt to be auto-discovered.

SNMP rate calculations [4]

Certain SNMP values are not useful themselves, but may be useful to watch after performing some manipulation. InOctets by itself is not useful, but using it to calculate a rate (or bandwidth use) in Bytes (or Bits) per second and comparing that value to a max or min is useful.

	Service UDP/SNMP {
		label:		Out
		hostname:       cisco-1.example.com
		# OutOctets
		oid:		.1.3.6.1.2.1.2.2.1.16.2
		calc:		ave-rate-bits
		maxvalue:	20000000	# 20M bits/sec
		minvalue:	 1000000	#  1M bits/sec
	}

This will convert the OutOctets value into a rate (Bytes per second), calculate the moving average, and convert it to Bits per second. If the resulting value falls outside the expected range of 1-20 Mbps, the test will fail.

The calc parameter was known as snmpcalc prior to version 3.2

TCP/URL Content Test

The TCP/HTTP tests that the HTTP service is up and running. The TCP/URL test will test the content of a web page.

	Service TCP/URL {
		url:	 http://www.example.com/cgi-bin/shoppingcart.pl
		browser: Mozilla/5.0 (compatible; just testing)
		expect:	 cart contains 1 item
	}
  • url the url to fetch. it must begin with 'http://', and may contain an optional ':port'. It needs to be specified.

  • expect a regular expression that needs to match the data received from the remote server. This needs to be specified. If nothing is specified, success or failure is determined by whether or not we received any data at all

  • browser spoof the specified browser (send as the User-Agent). This is optional, and can be used if the server or application is serving different content based on browser.

DNS Authoritativeness Test

The UDP/DNS (and UDP/DNSQ) test that a DNS server is up and running. The UDP/Domain test will test that a server is answering authoritatively for a zone.

	Service UDP/Domain {
		hostname:	ns1.example.com
		zone:		example.com
	}
  • hostname the hostname or IP address to query. This needs to be specified, but will propagate from an enclosing group

  • zone the DNS zone to check.

as a shortcut, an alternative syntax is supported:

	Group "nameserver" {
		hostname:	ns1.example.com
		Service UDP/Domain/example.com
		Service UDP/Domain/example.net
		Service UDP/Domain/example.org
	}

RPC tests

RPC testing is available only in versions 3.4 and later

Both TCP and UDP RPC services can be tested. The RPC tests will query the RPC portmapper to learn the service's current port.

	Service UDP/RPC
		hostname:	ns1.example.com
		prognum:	100003
		version:	2
	}
  • hostname the hostname or IP address to query. This needs to be specified, but will propagate from an enclosing group

  • prognum the RPC program number. this must be specified. many common RPC services can also be specified by name.

  • version the RPC program version. will default to 0.

as a shortcut, an alternative syntax is supported:


	Group "server" {
		hostname:	server.example.com

		# Service UDP/RPC/program/version

		Service UDP/RPC/100003
		Service UDP/RPC/100003/2
		Service TCP/RPC/mountd
		Service TCP/RPC/mountd/2
	}

[1] - UDP/DNS sends a 'status-query', UDP/DNSQ sends an 'IN ANY' query. some DNS servers (notably djbdns) do not handle 'status' queries. UDP/DNSQ is available only in versions 3.1 and later.

[2] - UDP/NFS tests NFS version 2. UDP/NFSv3 is NFS version 3. UDP/NFSv3 is available only in versions 3.1 and later.

[3] - This test uses the server-status query, which is not supported by all radius servers.

[4] - SNMP rate calculations are available only in versions 3.1.1 and later.

[5] - only available in versions 3.3 and later.

[6] - only available in versions 3.4 and later.

[7] - only available in versions 3.5 and later.