Farmer > API Overview > Resources > Network Security Group

Network Security Group

Overview

The Network Security Group builder creates network security groups with rules for securing network access to resources.

Network Security Groups (Microsoft.Network/networkSecurityGroups)
Security Rules (Microsoft.Network/networkSecurityGroups/securityRules)
Application Security Groups (Microsoft.Network/networkSecurityGroups)

Builder Keywords

Applies To	Keyword	Purpose
nsg	name	Specifies the name of the network security group
nsg	add_rules	Adds security rules to the network security group
nsg	initial_rule_priority	The priority of the first rule, after which each rule gets an incrementally higher value. Default 100.
nsg	priority_incr	This sets how much priority is increased per each rule. Default 100.
securityRule	name	The name of the security rule
securityRule	description	The description of the security rule
securityRule	services	The services port(s) and protocol(s) protected by this security rule
securityRule	add_source	Specify access from any source protocol, address, and port
securityRule	add_source_any	Specify access from any address and any port
securityRule	add_source_address	Specify access from a specific address and any port
securityRule	add_source_application_security_group	Specify access from an application security group
securityRule	add_source_network	Specify access from a specific network and any port
securityRule	add_source_tag	Specify access from a tagged source such as “Internet”, “VirtualNetwork”, or “AzureLoadBalancer”
securityRule	add_destination	Specify access to any source protocol, address, and port
securityRule	add_destination_any	Specify access to any address and any port
securityRule	add_destination_address	Specify access to a specific address and any port
securityRule	add_destination_application_security_group	Specify access to an application security group
securityRule	add_destination_network	Specify access from a specific network and any port
securityRule	add_destination_tag	Specify access to a tagged destination such as “Internet”, “VirtualNetwork”, or “AzureLoadBalancer”
securityRule	allow	Allows this traffic (the default)
securityRule	deny	Denies this traffic
securityRule	direction	Specify the direction of traffic controlled by the rule - inbound (the default) or outbound.
securityRule	priority	Explicitly specify the priority of a security rule.
securityRule	link_to_network_security_group	Specify the nsg when creating a security rule for an existing security group.
applicationSecurityGroup	name	Name of the Application Security Group.

Basic Example

open Farmer
open Farmer.Builders
open Farmer.NetworkSecurity

// Create a rule for https services accessible from the internet
let httpsAccess = securityRule {
    name "web-servers"
    services [ NetworkService ("https", Port 443us) ]
    add_source_tag TCP "Internet"
    add_destination_any
}
// Create an NSG and add the rule to it.
let myNsg = nsg {
    name "my-nsg"
    add_rules [
        httpsAccess
    ]
}

Multiple Tier Private Network Example

open Farmer
open Farmer.Builders
open Farmer.NetworkSecurity

// Many services have a few ports, such as web services that are often on 80 and 443.
// Some services only have a single port
// Different tiers may reside on different network segments
let corporateNet = "172.24.0.0/20"
let webNet = "10.100.30.0/24"
let appNet = "10.100.31.0/24"
let dbNet = "10.100.32.0/24"

// Create a rule for web servers - the 'web' service, accessible from the corporate network
let webAccess = securityRule {
    name "web-servers"
    description "Public web server access"
    services [
        NetworkService ("http", Port 80us)
        NetworkService ("https", Port 443us)
    ]
    add_source_network TCP corporateNet
    add_destination_network webNet
}

// Create another rule for app servers - accessible only from network with the web servers
let appAccess= securityRule {
    name "app-servers"
    description "Internal app server access"
    services [ NetworkService ("http", Port 8080us) ]
    add_source_network TCP webNet
    add_destination_network appNet
}

// Create another rule for DB servers - accessible only from network with the app servers
let dbAccess = securityRule {
    name "db-servers"
    description "Internal database server access"
    services [ NetworkService ("postgres", Port 5432us)]
    add_source_network TCP appNet
    add_destination_network dbNet
}

// Create an NSG and add all 3 rules to it.
let myNsg = nsg {
    name "my-nsg"
    add_rules [
        webAccess
        appAccess
        dbAccess
    ]
}