Google Compute Engine Firewall

google_compute_firewall (Terraform)

The Firewall in Compute Engine can be configured in Terraform with the resource name google_compute_firewall. The following sections describe how to use the resource and its parameters.

Example Usage from GitHub

An example could not be found in GitHub.

Security Best Practices for google_compute_firewall

There are 2 settings in google_compute_firewall that should be taken care of for security reasons. The following section explain an overview and example code.

Ensure your VPC firewall blocks unwanted outbound traffic

It is better to block unwanted outbound traffic not to expose resources in the VPC to unwanted attacks.

Ensure your VPC firewall blocks unwanted inbound traffic

It is better to block unwanted inbound traffic not to expose resources in the VPC to unwanted attacks.

Parameters

• creation_timestamp optional computed - string

Creation timestamp in RFC3339 text format.

• description optional - string

An optional description of this resource. Provide this property when you create the resource.

• destination_ranges optional computed - set of string

If destination ranges are specified, the firewall will apply only to traffic that has destination IP address in these ranges. These ranges must be expressed in CIDR format. Only IPv4 is supported.

• direction optional computed - string

Direction of traffic to which this firewall applies; default is INGRESS. Note: For INGRESS traffic, it is NOT supported to specify destinationRanges; For EGRESS traffic, it is NOT supported to specify sourceRanges OR sourceTags. Possible values: ["INGRESS", "EGRESS"]

• disabled optional - bool

Denotes whether the firewall rule is disabled, i.e not applied to the network it is associated with. When set to true, the firewall rule is not enforced and the network behaves as if it did not exist. If this is unspecified, the firewall rule will be enabled.

• enable_logging optional computed - bool

This field denotes whether to enable logging for a particular firewall rule. If logging is enabled, logs will be exported to Stackdriver.

• id optional computed - string
• name required - string

Name of the resource. Provided by the client when the resource is created. The name must be 1-63 characters long, and comply with RFC1035. Specifically, the name must be 1-63 characters long and match the regular expression 'a-z?' which means the first character must be a lowercase letter, and all following characters must be a dash, lowercase letter, or digit, except the last character, which cannot be a dash.

• network required - string

The name or self_link of the network to attach this firewall to.

• priority optional - number

Priority for this rule. This is an integer between 0 and 65535, both inclusive. When not specified, the value assumed is 1000. Relative priorities determine precedence of conflicting rules. Lower value of priority implies higher precedence (eg, a rule with priority 0 has higher precedence than a rule with priority 1). DENY rules take precedence over ALLOW rules having equal priority.

• project optional computed - string
• self_link optional computed - string
• source_ranges optional computed - set of string

If source ranges are specified, the firewall will apply only to traffic that has source IP address in these ranges. These ranges must be expressed in CIDR format. One or both of sourceRanges and sourceTags may be set. If both properties are set, the firewall will apply to traffic that has source IP address within sourceRanges OR the source IP that belongs to a tag listed in the sourceTags property. The connection does not need to match both properties for the firewall to apply. Only IPv4 is supported.

• source_service_accounts optional - set of string

If source service accounts are specified, the firewall will apply only to traffic originating from an instance with a service account in this list. Source service accounts cannot be used to control traffic to an instance's external IP address because service accounts are associated with an instance, not an IP address. sourceRanges can be set at the same time as sourceServiceAccounts. If both are set, the firewall will apply to traffic that has source IP address within sourceRanges OR the source IP belongs to an instance with service account listed in sourceServiceAccount. The connection does not need to match both properties for the firewall to apply. sourceServiceAccounts cannot be used at the same time as sourceTags or targetTags.

• source_tags optional - set of string

If source tags are specified, the firewall will apply only to traffic with source IP that belongs to a tag listed in source tags. Source tags cannot be used to control traffic to an instance's external IP address. Because tags are associated with an instance, not an IP address. One or both of sourceRanges and sourceTags may be set. If both properties are set, the firewall will apply to traffic that has source IP address within sourceRanges OR the source IP that belongs to a tag listed in the sourceTags property. The connection does not need to match both properties for the firewall to apply.

• target_service_accounts optional - set of string

A list of service accounts indicating sets of instances located in the network that may make network connections as specified in allowed[]. targetServiceAccounts cannot be used at the same time as targetTags or sourceTags. If neither targetServiceAccounts nor targetTags are specified, the firewall rule applies to all instances on the specified network.

• target_tags optional - set of string

A list of instance tags indicating sets of instances located in the network that may make network connections as specified in allowed[]. If no targetTags are specified, the firewall rule applies to all instances on the specified network.

• allow set block
  • ports optional - list of string

  An optional list of ports to which this rule applies. This field is only applicable for UDP or TCP protocol. Each entry must be either an integer or a range. If not specified, this rule applies to connections through any port. Example inputs include: ["22"], ["80","443"], and ["12345-12349"].

  • protocol required - string

  The IP protocol to which this rule applies. The protocol type is required when creating a firewall rule. This value can either be one of the following well known protocol strings (tcp, udp, icmp, esp, ah, sctp, ipip, all), or the IP protocol number.

• deny set block
  • ports optional - list of string

  An optional list of ports to which this rule applies. This field is only applicable for UDP or TCP protocol. Each entry must be either an integer or a range. If not specified, this rule applies to connections through any port. Example inputs include: ["22"], ["80","443"], and ["12345-12349"].

  • protocol required - string

  The IP protocol to which this rule applies. The protocol type is required when creating a firewall rule. This value can either be one of the following well known protocol strings (tcp, udp, icmp, esp, ah, sctp, ipip, all), or the IP protocol number.

• log_config list block
  • metadata required - string

  This field denotes whether to include or exclude metadata for firewall logs. Possible values: ["EXCLUDE_ALL_METADATA", "INCLUDE_ALL_METADATA"]

• timeouts single block
  • create optional - string
  • delete optional - string
  • update optional - string

Explanation in Terraform Registry

Each network has its own firewall controlling access to and from the instances. All traffic to instances, even from other instances, is blocked by the firewall unless firewall rules are created to allow it. The default network has automatically created firewall rules that are shown in default firewall rules. No manually created network has automatically created firewall rules except for a default "allow" rule for outgoing traffic and a default "deny" for incoming traffic. For all networks except the default network, you must create any firewall rules you need. To get more information about Firewall, see:

• API documentation
• How-to Guides
  • Official Documentation

Tips: Best Practices for The Other Google Compute Engine Resources

In addition to the google_compute_disk, Google Compute Engine has the other resources that should be configured for security reasons. Please check some examples of those resources and precautions.

google_compute_disk

Ensure the encryption key for your GCE disk is stored securely

It is better to store the encryption key for your GCE disk securely. Secret Manager could be used instead.

google_compute_instance

Ensure appropriate service account is assigned to your GCE instance

It is better to create a custom service account for the instance and assign it.

google_compute_project_metadata

Ensure OS login for your GCE instances is enabled at project level

It is better to enable OS login for your GCE instances. Enabling OS login ensures that SSH keys used to connect to instances are mapped with IAM users, allowing centralized and automated SSH key management.

google_compute_ssl_policy

Ensure to use modern TLS protocols

It's better to adopt TLS v1.2+ instead of outdated TLS protocols.

google_compute_subnetwork

Ensure VPC flow logging is enabled

It is better to enable VPC flow logging. VPC flow logging allows us to audit traffic in your network.