config system health-check

Use this command to create health check configuration objects.

In server load balancing deployments, the system uses health checks to poll the members of the real server pool to test whether an application is available. You can also configure additional health checks to poll related servers, and you can include results for both in the health check rule. For example, you can configure an HTTP health check test and a RADIUS health check test. In a web application that requires user authentication, the web server is deemed available only if the web server and the related RADIUS server pass the health check.

In link load balancing deployments, the health check can poll either the ISP link group member itself or a “beacon” server that is deployed on the other side of the ISP link. A beacon is an IP address that must be reachable in order for the link to be deemed available. A beacon can be any IP address, such as a main office, core router, or virtual server at another data center.

If a pool member fails a health check and retries also fail, it is deemed unavailable. The ADC does not send it connections until it is deemed available.

If you expect a backend server is going to be unavailable for a long period, such as when it is undergoing hardware repair, it is experiencing extended down time, or when you have removed it from the server farm, you can improve the performance of the FortiADC system by setting the status of the pool member to Disabled, rather than allowing the system to continue to attempt health checks.

Table 21 describes the predefined health checks. You can get started with these or create custom objects.

Predefined health check configuration objects
Predefined	Description
LB_HLTHCK_HTTP	Sends a HEAD request to the server port 80. Expects the server to return an HTTP 200.
LB_HLTHCK_HTTPS	Sends a HEAD request to the server port 443. Expects the server to return an HTTP 200.
LB_HLTHCK_ICMP	Pings the server.
LB_HLTHCK_TCP_ECHO	Sends a TCP echo to server port 7. Expects the server to respond with the corresponding TCP echo.

Before you begin:

You must have a good understanding of TCP/IP and knowledge of the services running on your backend servers.
You must know the IP address, port, and configuration details for the applications running on backend servers. For some application protocol checks, you must specify user credentials.
You must have read-write permission for load balancing settings.

After you have configured a health check, you can select it in the server load balacing real server configuration or in the link-load-balancing gateway link configuration.

Syntax

config system health-check

edit <name>

set type {diameter | dns | ftp | http | https | icmp | imap4 | l2-detection | ldap | ldaps | mssql | mysql | oracle | pop3 | radacct | radius | rtsp | script | sip | sip-tcp | smtp | snmp | snmp-custom | ssh | tcp | tcp-echo | tcphalf | tcpssl | udp}

set dest-addr-type {ipv4 | ipv6 | fqdn}

set dest-addr <ipv4 or ipv6>

set fqdn <fqdn>

set hostname <string>

set interval <integer>

set retry <integer>

set timeout <integer>

set up-retry <integer>

set port <integer>

set method-type {http_get | http_head}

set send-string <string>

set receive-string <string>

set status-code <integer>

set match-type {match_all | match_status | match_string}

set http-connect {local_connect | no_connect | remote_connect}

set http-version {http_1.0 | http_1.1}

set additional-string <additional string for http header content>

set remote-host <string>

set remote-port <integer>

set addr-type {ipv4 | ipv6}

set domain-name <string>

set host-addr <class_ip>

set nas-ip <string>

set username <username>

set password <password>

set password-type {user-password | chap-password}

set secret-key <string>

set sip-request-type {register|options}

set folder <string>

set file <string>

set passive {enable|disable}

set agent-type {UCD|WIN2000}

set community <string>

set cpu <integer>

set disk <integer>

set mem <integer>

set version {v1|v2c}

config snmp-custom

edit <name>

set oid <string>

set value-type {ASN_COUNTER | ASN_INTEGER | ASN_OCTET_STR | ASN_UINTEGER}

set compare-type {equal | greater | less }

set counter-value <integer>

set name <string>

set weight <integer>

set origin-host <string>

set origin-realm <string>

set vendor-id <integer>

set product-name <string>

set host-ip-addr <class_ip>

set host-ip6-addr <class_ip>

set auth-appid <integer>

set acct-appid <integer>

set connect-data-type {connect_string | service_name | sid}

set service_name <string>

set sid <string>

set connect-string <string>

set oracle-send-string <string>

set oracle-receive-string <string>

set script {<datasource> | CURL_HTTP_CODE | ICMP | PORT_STATUS }

set attribute <string>

set baseDN <string>

set bindDN <string>

set filter <string>

set database <string>

set mssql-send-string <string>

set mssql-receive-string <string>

set verify-host-cert {enable | disable}

set ca <datasource>

end

Health check configuration
Settings	Guidelines
General
<name>	Configuration name. No spaces or special characters. After you initially save the configuration, you cannot edit the name.
type	Specify the health check type. After you have specified the type, the CLI commands are constrained to the ones that are applicable to the specified type, not all of the settings described in this table. diameter dns ftp http https icmp imap4 l2-detection ldap ldaps mssql mysql oracle pop3 radacct radius rtsp script sip sip-tcp smtp snmp snmp-custom ssh tcp tcp-echo tcphalf tcpssl udp
dest-addr-type	Specify the destination address type. ipv4 ipv6 fqdn — destination FQDN type is only supported for LDAP and LDAPS health check types. Note: For the LDAP or LDAPS health check types, if Verify Host Certificate is enabled, the destination address type must match the CN in the LDAP/S server certificate as either IP address or FQDN. For example, if the CN in the LDAP/S server certificate is FQDN, then the destination address in the health check configuration must be FQDN as well.
dest-addr	The dest-addr option is available if dest-addr-type is ipv4 or ipv6. Optional. If no destination IP address is specified, the real server health check is sent to the real server IP address and the gateway link health check is sent to the ISP link IP address. If you are creating rules that test related servers or a test to a “beacon” server, specify the destination IP address. If testing an HTTP proxy, specify the proxy address, not the remote server address.
fqdn	The fqdn option is available if dest-addr-type is fqdn. Specify the destination FQDN (Fully Qualified Domain Name).
hostname	For HTTP or HTTPS health checks, you can specify the hostname (FQDN) instead of the destination IP address. This is useful in VM environments where multiple applications have the same IP address.
interval	Seconds between each health check. Should be more than the timeout to prevent overlapping health checks. The default is 10.
retry	Attempts to retry the health check to confirm availability. The default is 1.
timeout	Seconds to wait for a reply before assuming that the health check has failed. The default is 5.
up-retry	Attempts to retry the health check to confirm availability. The default is 1.
ICMP
No specific options	Simple ping to test connectivity.
TCP / TCP Half Open / TCP SSL / UDP
port	Listening port number of the backend server. Usually HTTP is 80, FTP is 21, DNS is 53, POP3 is 110, IMAP4 is 143, RADIUS is 1812, and SNMP is 161 or 162.
HTTP/HTTPS
port	Listening port number of the backend server. Usually HTTP is 80. If testing an HTTP proxy server, specify the proxy port.
method-type	HTTP method for the test traffic: HTTP GET—Send an HTTP GET request to the server. A response to an HTTP GET request includes HTTP headers and HTTP body. HTTP HEAD—Send an HTTP HEAD request. A response to an HTTP HEAD request includes HTTP headers only.
send-string	The request URL, such as /contact.php.
receive-string	A string expected in return when the HTTP GET request is successful.
status-code	The health check sends an HTTP request to the server. Specify the HTTP status code in the server reply that indicates a successful test. Typically, you use status code 200 (OK). Other status codes indicate errors.
match-type	What determines a failed health check? Match String Match Status Match All (match both string and status) Not applicable when using HTTP HEAD. HTTP HEAD requests test status code only.
http-connect	If the real server pool members are HTTP proxy servers, specify an HTTP CONNECT option: local_connect—Use HTTP CONNECT to test the tunnel connection through the proxy to the remote server. The member is deemed available if the request returns status code 200 (OK). remote_connect—Use HTTP CONNECT to test both the proxy server response and remote server application availability. If you select this option, you can configure an HTTP request within the tunnel. For example, you can configure an HTTP GET/HEAD request to the specified URL and the expected response. no_connect—Do not use the HTTP CONNECT method. This option is the default. The HTTP CONNECT option is useful to test the availability of proxy servers only. See the FortiADC Deployment Guide for FortiCache for an example that uses this health check.
http-version	Specify the version of HTTP
additional-string	attach some string to HTTP header content
remote-host	If you use HTTP CONNECT to test proxy servers, specify the remote server IP address.
remote-port	If you use HTTP CONNECT to test proxy servers, specify the remote server port.
DNS
addr-type	IPv4 or IPv6
domain-name	The FQDN, such as www.example.com, to use in the DNS A/AAAA record health check.
host-addr	IP address that matches the FQDN, indicating a successful DNS health check.
RADIUS / RADIUS Accounting
port	Listening port number of the backend server. Usually RADIUS is 1812 and RADIUS accounting is 1813.
nas-ip	NAS IP address.
username	User name of an account on the backend server.
password	The corresponding password.
password-type	User—If the backend server does not use CHAP, select this option. CHAP—If the backend server uses CHAP and does not require a secret key, select this option.
secret-key	The secret set on the backend server.
SIP / SIP TCP
sip-request-type	Specify the SIP request type to be used for health checks: register options
status-code	The expected response code. If not set, response code 200 is expected. Specify `0` if any reply should indicate the server is available.
SMTP
port	Listening port number of the backend server. Usually SMTP is 25.
domain-name	The FQDN, such as www.example.com, to use in the SMTP health check.
POP3
port	Listening port number of the backend server. Usually POP3 is 110.
username	User name of an account on the backend server.
password	The corresponding password.
IMAP4
port	Listening port number of the backend server. Usually IMAP4 is 143.
username	User name of an account on the backend server.
password	The corresponding password.
folder	Specify a mail folder name. The default is INBOX.
FTP
port	Listening port number of the backend server. Usually FTP is 21.
username	User name of an account on the backend server.
password	The corresponding password.
file	Specify a file that exists on the backend server. Path is relative to the initial login path. If the file does not exist or is not accessible, the health check fails.
passive	Select this option if the backend server uses passive FTP.
SNMP
port	Listening port number of the backend server. Usually SNMP is 161.
agent-type	UCD or Windows 2000
community	Must match the SNMP community string set on the backend server. If this does not match, all SNMP health checks fail.
cpu	Maximum normal CPU usage. If overburdened, the health check fails.
disk	Maximum normal disk usage. If the disk is too full, the health check fails.
mem	Maximum normal RAM usage. If overburdened, the health check fails.
version	SNMP v1 or v2c.
SNMP Custom
port	Listening port number of the backend server. Usually SNMP is 161 or 162.
community	Must match the SNMP community string set on the backend server. If this does not match, all SNMP health checks fail.
version	SNMP v1 or v2c.
config snmp-custom
oid	String specifying the OID to query.
value-type	Abstract syntax notation (ASN) value type: ASN_COUNTER ASN_INTEGER ASN_OCTET_STR ASN_UINTEGER
compare-type	equal greater less The default option is less.
counter-value	Specify the value for the evaluation. The range is 1-2147483647.
name	Specify the SNMP custom name.
weight	Specify the SNMP custom weight.
SSH
port	Listening port number of the backend server. Usually SSH is 22.
username	Username for test login.
password	Corresponding password.
L2 Detection
No specific options	Link Layer health checker. Sends ARP (IPv4) or NDP (IPv6) packets to test whether a physically connected system is available.
MySQL
`username`	Specify the user name of the MySQL database.
`password`	Specify the password corresponding to the MySQL database user name.
`dest-addr`	Specify the IP address of the MySQL database server.
`port`	Listening port number of the backend server.
Diameter
origin-host	Specify the FortiADC appliance that originates the Diameter message. The value is in FQDN format and used to uniquely identify a Diameter node for duplicate connection and routing loop detection. Note: Some Diameter servers do not accept multiple connections from the same origin host. If you set the origin host the same as the origin host (Identity) of the Diameter load-balance profile and use the health check and Diameter load balance profile in the same virtual server, the health check or the Diameter load-balance profile may run into certain undefined problems.
origin-realm	Specify the realm of the FortiADC appliance that originates the Diameter message. The value is in FQDN format.
vendor-id	Specify the type Unsigned32 vendor ID which contains the IANA "SMI Network Management Private Enterprise Codes" value assigned to the vendor of a Diameter application. The default is 12356.
product-name	Specify the type UTF8String product name which contains the vendor assigned name for the product.
host-ip-addr	Specify the type IPv4 address used to inform a Diameter peer of the sender's IP address when the destination address type is IPv4. The default is blank, meaning that it is the address of the FortiADC's outgoing interface.
host-ip6-addr	Specify the type IPv6 address used to inform a Diameter peer of the sender's IP address when the destination address type is IPv6. The default is blank, meaning that it is the address of the FortiADC's outgoing interface.
auth-appid	Specify the type Unsigned32 authentication application ID used to advertise support of the authentication and authorization portion of an application. This filed is optional; the default is 0 (zero).
acct-appid	Specify the type Unsigned32 accounting application ID used to advertise support of the accounting portion of an application. This field is optional; the default is 0 (zero).
Oracle
`port`	Listening port number of the OracleDB server
`username`	Specify the database username
`password`	Specify the database password
`connect-data-type`	Select either of the following: service_name sid connect_string Setting these configurations depends on the configuration of the server.
`service_name`	When you select a Service name, use this to specify the Service name.
`sid`	When you select an SID, use this to specify the SID.
`connect-string`	When you select a service name, use this to specify connect string.
`oracle-send-string`	Send a string (command) to OracleDb server.
`oracle-receive-string`	The string we expect to receive.
`row`	The row in which the send string (command) takes effect.
`column`	The column in which the send string (command) takes effect.
Script
`port`	Specify the port that is used by the script.
`script`	Specify the script we create or pre-define. Predefined scripts: CURL_HTTP_CODE ICMP PORT_STATUS
LDAP
port	Port Listening port number of the backend server. Usually LDAP is 389.
password	The corresponding password.
attribute	Attributes for the LDAP health check object.
baseDN	The distinguished name where a LDAP server will search from.
bindDN	The distinguished name used to bind to a LDAP server.
filter	Criteria to use in selecting results.
MSSQL
port	Specify the listening port number of the MSSQL server. Valid values range from 0 to 65535.
username	Specify the database user name. (Optional)
password	Specify the database password, if applicable.
database	Specify the name of the MSSQL database.
mssql-send-string	Specify the MSSQL send string.
mssql-receive-string	Specify the MSSQL receive string.
row	The row in which the send string (command) takes effect.
column	The column in which the send string (command) takes effect.
LDAPS
port	Port Listening port number of the backend server. The default port is 636 for LDAPS.
password	The corresponding password.
bindDN	The distinguished name used to bind to a LDAPS server.
baseDN	The distinguished name where a LDAPS server will search from.
filter	Criteria to use in selecting results.
attribute	Attributes for the LDAPS health check object.
verify-host-cert	Enable to verify the LDAPS server certificate. This is disabled by default.
ca	The CA option is available if Verify Host Certificate is enabled. Specify the CA certificate.

In SLB deployments, a health check port configuration specifying port 0 acts as a wildcard.The port for health check traffic is imputed from the real server pool member.

In LLB and GLB deployments, specifying port 0 is invalid because there is no associated configuration to impute a proper port. If your health check port configuration specifies port 0, you will not be able to use it in an LLB or GLB configuration.

Example

The following is an example of an HTTP health check for HTTP proxy servers:

FortiADC-VM # config system health-check

FortiADC-VM (health-check) # edit HTTP-CONNECT-TEST

Add new entry 'HTTP-CONNECT-TEST' for node 2763

FortiADC-VM (HTTP-CONNECT-T~S) # set type http

FortiADC-VM (HTTP-CONNECT-T~S) # set http-connect remote_connect

FortiADC-VM (HTTP-CONNECT-T~S) # get

type : http

interval : 10

timeout : 5

retry : 1

up-retry : 1

port : 0

dest-addr-type : ipv4

dest-addr : 0.0.0.0

method-type : http_head

send-string : /

status-code : 200

http-connect : remote_connect

remote-host :

remote-port : 0

FortiADC-VM (HTTP-CONNECT-T~S) # set remote-host 10.1.1.1

FortiADC-VM (HTTP-CONNECT-T~S) # set remote-port 113

FortiADC-VM (HTTP-CONNECT-T~S) # set send-string /myapp/index.html

FortiADC-VM (HTTP-CONNECT-T~S) # end

FortiADC-VM #

The following is an example of a SIP health check:

FortiADC-VM # config system health-check

FortiADC-VM (health-check) # edit sip-health-check

Add new entry 'sip-health-check' for node 2763

FortiADC-VM (sip-health-check) # set type sip

FortiADC-VM (sip-health-check) # get

type : sip

interval : 10

timeout : 5

retry : 1

up-retry : 1

port : 0

dest-addr-type : ipv4

dest-addr : 0.0.0.0

status-code : 200

sip-request-type : register

FortiADC-VM (sip-health-check) # set interval 15

FortiADC-VM (sip-health-check) # set retry 2

FortiADC-VM (sip-health-check) # set timeout 3

FortiADC-VM (sip-health-check) # set status-code 403

FortiADC-VM (sip-health-check) # end

The following is an example of an SNMP health check for a server running the UCD agent:

FortiADC-VM # config system health-check

FortiADC-VM (health-check) # edit lb-health-check

Add new entry 'lb-health-check' for node 2763

FortiADC-VM (lb-health-check) # set type snmp

FortiADC-VM (lb-health-check) # get

type : snmp

interval : 10

timeout : 5

retry : 1

up-retry : 1

port : 0

dest-addr-type : ipv4

dest-addr : 0.0.0.0

cpu : 96

mem : 96

disk : 96

agent-type : UCD

community :

version : v1

FortiADC-VM (lb-health-check) # set community company-string

FortiADC-VM (lb-health-check) # set port 161

FortiADC-VM (lb-health-check) # set cpu 50

FortiADC-VM (lb-health-check) # set mem 50

FortiADC-VM (lb-health-check) # set disk 50

FortiADC-VM (lb-health-check) # set version v2c

FortiADC-VM (lb-health-check) # get

type : snmp

interval : 10

timeout : 5

retry : 1

up-retry : 1

port : 161

dest-addr-type : ipv4

dest-addr : 0.0.0.0

cpu : 50

mem : 50

disk : 50

agent-type : UCD

community : company-string

version : v2c

FortiADC-VM (lb-health-check) # end

The following example configures a custom SNMP health check for a server that does not support the UCD or Windows 2000 agent type.

FortiADC-VM # config system health-check

FortiADC-VM (health-check) # edit snmp-linux

Add new entry 'snmp-linux' for node 2763

FortiADC-VM (snmp-linux) # set type snmp-custom

FortiADC-VM (snmp-linux) # get

type : snmp-custom

interval : 10

timeout : 5

retry : 1

up-retry : 1

port : 0

dest-addr-type : ipv4

dest-addr : 0.0.0.0

community :

version : v1

oid :

value-type :

FortiADC-VM (snmp-linux) # set version v2c

FortiADC-VM (snmp-linux) # set oid ".1.3.6.1.4.1.2021.10.1.3.1"

FortiADC-VM (snmp-linux) # set value-type ASN_INTEGER

FortiADC-VM (snmp-linux) # set compare-type greater

FortiADC-VM (snmp-linux) # set counter-value 80

FortiADC-VM (snmp-linux) # end

FortiADC-VM #