Using IAP for TCP forwarding  |  Identity-Aware Proxy  |  Google Cloud (2024)

Console

To allow RDP and SSH access to all VM instances in your network, do the following:

1. Open the Firewall Rules page.

   Open the Firewall Rules page

2. On the Firewall Rules page, click Create firewall rule.
3. Configure the following settings:
   • Name: allow-ingress-from-iap
   • Direction of traffic: Ingress
   • Target: All instances in the network
   • Source filter: IP ranges
   • Source IP ranges: 35.235.240.0/20
   • Protocols and ports: Select TCP and enter 22,3389 to allow both RDP and SSH.
4. Click Create.

gcloud

To allow RDP access to all VM instances in your network, run:

gcloud compute firewall-rules create allow-rdp-ingress-from-iap \ --direction=INGRESS \ --action=allow \ --rules=tcp:3389 \ --source-ranges=35.235.240.0/20

For SSH access, run:

gcloud compute firewall-rules create allow-ssh-ingress-from-iap \ --direction=INGRESS \ --action=allow \ --rules=tcp:22 \ --source-ranges=35.235.240.0/20

For other protocols, run

gcloud compute firewall-rules create allow-ingress-from-iap \ --direction=INGRESS \ --action=allow \ --rules=tcp:PORT \ --source-ranges=35.235.240.0/20

where PORT is the port used by the protocol.

Console

1. Open the IAM & Admin page in the Google Cloud console.

2. On the IAM & Admin page, click Add and configure the following:
   • New principals: Specify the user or group you want to grant access.
   • Select a role: Select Cloud IAP > IAP-Secured Tunnel User.
3. Optionally, click Add condition and configure a member restriction:
   • Title: Enter a name for the restriction.
   • Expression: Enter a condition that a user must meet before being allowed to use IAP for TCP forwarding.

   For example, the following CEL expression restricts access to port 22:

   destination.port == 22

   You can also restrict access by access level:

   destination.port == 22 &&"FULL_ACCESS_LEVEL_NAME" in request.auth.access_levels

   Where FULL_ACCESS_LEVEL_NAME is an existing access level and uses the following format:

   accessPolicies/POLICY_NAME/accessLevels/ACCESS_LEVEL_NAME

4. Click Add another role and configure the following:
   • Select a role Select Compute Engine > Compute Instance Admin (v1).
5. Click Save.

gcloud

Grant the two roles to the user by running the following commands:

gcloud projects add-iam-policy-binding PROJECT_ID \ --member=user:EMAIL \ --role=roles/iap.tunnelResourceAccessorgcloud projects add-iam-policy-binding PROJECT_ID \ --member=user:EMAIL \ --role=roles/compute.instanceAdmin.v1

Replace the following:

• PROJECT_ID: ID of the project
• EMAIL: email address of the user you want to grant access,for example user@example.com.

Console

1. Open the IAP admin page and select the SSH and TCP Resources tab.

   Open the IAP admin page

2. On the SSH and TCP Resources tab of the IAP admin page, select the VM instances that you want to configure.
3. Click Show info panel if the info panel is not visible.

4. Click Add member and configure the following:

   • New principals: Specify the user or group you want to grant access.
   • Select a role: Select Cloud IAP > IAP-Secured Tunnel User.

5. Optionally, click Add condition and configure a member restriction:

   • Title: Enter a name for the restriction.
   • Expression: Enter a condition that a user must meet before being allowed to use IAP for TCP forwarding.

   For example, the following CEL expression restricts access to port 22:

    destination.port == 22

   You can also restrict access by access level:

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    destination.port == 22 && "FULL_ACCESS_LEVEL_NAME" in request.auth.access_levels

   Where FULL_ACCESS_LEVEL_NAME is an existing [access level](/access-context-manager/docs/create-access-level) and uses the format accessPolicies/POLICY_NAME/accessLevels/ACCESS_LEVEL_NAME.

6. Click Save.

API

To edit your application's policy.json file, follow the process below. See Managing access to IAP-secured resources for more information about using the IAM API to manage access policies.

1. Download the credentials file for your service account.

   1. Go to the Service accounts page.Go to the service accounts page

   2. Click the email address of your service account.

   3. Click Edit.

   4. Click Create key.

   5. Select JSON as your key type.

   6. Create a new key by clicking Create and closing the confirmation window that appears.

   Your JSON credentials file has now been downloaded.

2. Export the following variables.

   export IAP_BASE_URL=https://iap.googleapis.com/v1/projects/PROJECT_NUMBER/iap_tunnel# Replace with the path to your local service account's downloaded JSON fileexport JSON_CREDS=EXAMPLE.IAM.GSERVICEACCOUNT.COM.JSON# Replace POLICY_FILE.JSON with the name of JSON file to use for setIamPolicyexport JSON_NEW_POLICY=POLICY_FILE.JSON

3. Convert your service account credentials JSON file into an OAuth accesstoken using Oauth2l by running thefollowing command:

   oauth2l header --json ${JSON_CREDS} cloud-platform
   

4. If this is your first time running the above command, when prompted:

   1. Get the verification code by clicking the displayed link and copyingthe code.
   2. Paste the verification code into your app prompt.
   3. Copy the returned bearer token.
   4. Export a new variable that's assigned to the value of your returnedbearer token.

      export CLOUD_OAUTH_TOKEN=AUTHORIZATION_BEARER_TOKEN

5. If you've run this command before, export the following variable.

   export CLOUD_OAUTH_TOKEN="$(oauth2l header --json ${JSON_CREDS} cloud-platform)"

6. Get the IAM policy for the Compute Engine instance usingthe getIamPolicy method. The empty data bit at the end turns the curlrequest into POST instead of GET.

   curl -i -H "${CLOUD_OAUTH_TOKEN}" \ ${IAP_BASE_URL}/zones/ZONE_NAME/instances/INSTANCE_ID or INSTANCE_NAME:getIamPolicy \ -d ''

7. Grant the iap.tunnelResourceAccessor role to your members bymodifying the IAM policy JSON file.

8. Optionally, add member restrictions based on IAMConditions and access levels.

   The following is an example of an edited policy.json file that bindsthe iap.tunnelResourceAccessor role to a group of VM instance admins,granting them access to IAP-secured tunnel resources.An IAM condition has been added to make the resourcesaccessible only to members in the VM instance admins group with a privateIP address of 10.0.0.1 on port 22 using thedestination.ip and destination.port IAM Conditions.They must also meet the requirements of the ACCESS_LEVEL_NAMEaccess level.

   Note that if a member has theOwner role, they have permission to use IAPfor TCP forwarding.

   
   Example policy.json file

   { "policy": { "bindings": [ { "role": "roles/iap.tunnelResourceAccessor", "members": ["group:instance-admins@example.com"], "condition": { "expression": "\"accessPolicies/POLICY_NAME/accessLevels/ACCESS_LEVEL_NAME\" in request.auth.access_levels && destination.ip == \"10.0.0.1\" && destination.port == 22", "title": "CONDITION_NAME" } } ] }}

   To find a policy name, call accessPolicies.list:

   GET https://accesscontextmanager.googleapis.com/v1/accessPolicies

9. Set your new policy.json file using the setIamPolicy method.

   curl -i -H "Content-Type:application/json" \ -H "$(oauth2l header --json ${JSON_CREDS} cloud-platform)" \ ${IAP_BASE_URL}/zones/ZONE_NAME/instances/INSTANCE_ID or INSTANCE_NAME:setIamPolicy \ -d @${JSON_NEW_POLICY}

Console

To connect to your instance, use the SSH button in theGoogle Cloud console.Your instance's access configuration(defined through IAM permissions) must allow TCPtunneling through IAP.

gcloud

To connect to your instance, use thegcloud compute ssh command. Yourinstance's access configuration(defined through IAM permissions) must allow TCPtunneling through IAP.

gcloud compute ssh INSTANCE_NAME

Replace INSTANCE_NAME with the name of the instance to SSH into.

If the instance doesn't have an external IP address, the connectionautomatically uses IAP TCP tunneling. If the instance doeshave an external IP address, the connection uses the external IP addressinstead of IAP TCP tunneling.

You can use the --tunnel-through-iapflag so that gcloud compute ssh always uses IAP TCP tunneling.

Use the --internal-ipflag so that gcloud compute ssh never uses IAP TCPtunneling and instead directly connects to the internal IP of the VM. Doingso is useful for clients that are connected to the same VPC network as thetarget VM.

IAP Desktop

You can use IAP Desktop to connect to a VM instance by using SSH and IAP TCP forwarding.

1. In the application, select File > Add Google Cloud project.

2. Enter the ID or name of your project and click OK.

3. In the Project Explorer window, right-click the VM instance youwant to connect to and select Connect.

For more information on IAP Desktop, see theGitHub project page.

PuTTY app

You can set up the PuTTY Windows terminal emulator app so that it usesIAP TCP forwarding to connect to a VM instance. Yourinstance's access configuration(defined through IAM permissions) must allow TCP tunneling through IAP.

Before you configure the PuTTY app, use the gcloud compute ssh command onceto ensure that you have a private SSH key on your local computer and thatyour public SSH key is published to Compute Engine:

1. Open a command prompt and run the following command to connect to theVM instance:

   gcloud compute ssh INSTANCE_NAME ` --tunnel-through-iap ` --project PROJECT_ID ` --zone ZONE

   Replace the following:

   • INSTANCE_NAME: name of the instance to connect to
   • PROJECT_ID: project ID of the project the VM instance is located in
   • ZONE: zone where the VM instance is located

   If necessary, confirm that you want to generate SSH keys by pressing Y.

2. On the VM, determine your username by running the following command:

   whoami

   You need this username later.

You can now configure the PuTTY app to use IAP TCP forwarding:

1. Open the PuTTY app and select the category Connection > Proxy.

2. Configure the following proxy settings:

   • For Proxy type, select Local.

   • In the Telnet command, or local proxy command field, enter the following:

     gcloud.cmd compute start-iap-tunnel %host %port --listen-on-stdin --project PROJECT_ID --zone ZONE

     Replace the following:

     • PROJECT_ID: Project ID of the project the VM instance is located in
     • ZONE: Zone where the VM instance is located

   • For Print proxy diagnostics in the terminal window, selectOnly until session starts.

3. Select the category Connection > SSH > Auth.

4. Click Browse and paste the following file name, then click Open:

   %USERPROFILE%\.ssh\google_compute_engine.ppk

5. Select the category Session.

6. Configure the following proxy settings:

   • In the Host name (or IP address) field, enter the following:

     USERNAME@INSTANCE_NAME

     Replace the following:

     • USERNAME: the Linux username you determined earlier
     • INSTANCE_NAME: the name of the VM instance that you want to connect to

   • Saved sessions: Enter a name for the session.

7. Click Save.

8. Click Open to start the SSH session.

ssh

You can directly use the ssh command with a ProxyCommand option that uses gcloudto start the tunnel. Use this to generate the full ssh command:

gcloud compute ssh INSTANCE_NAME --dry-run

IAP Desktop

You can use IAP Desktop to connect to the Remote Desktop of one or more VM instances by using IAP TCP forwarding.

1. In the application, select File > Add Google Cloud project.

2. Enter the ID or name of your project and click OK.

3. In the Project Explorer window, right-click the VM instance youwant to connect to and select Connect.

For more information on IAP Desktop, see theGitHub project page.

gcloud

To connect to the Remote Desktop of a VM instance, you first create a tunnel.

1. Use thegcloud compute start-iap-tunnelcommand to create an encrypted tunnel to the RDP port of the VM instance.

   gcloud compute start-iap-tunnel INSTANCE_NAME 3389 \ --local-host-port=localhost:LOCAL_PORT \ --zone=ZONE

   Replace INSTANCE_NAME with the name of the VM instance youwant to connect to. Replace LOCAL_PORT with the localhostport where you want the proxy to be bound or use 0 to have an unused oneselected automatically. Replace ZONE with the zone where theVM instance is located.

2. gcloud performs a connectivity test with the VM instance, then opens atunnel and shows a port number.

   Listening on port [LOCAL_PORT].

   All traffic sent to localhost:LOCAL_PORT is forwarded to theVM instance. The port is only accessible by applications running on yourlocal computer.

3. Leave gcloud running and open the Microsoft Windows Remote DesktopConnection app.

4. Enter the tunnel endpoint as computer name:

   localhost:LOCAL_PORT

   Replace LOCAL_PORT with the port number shown when the tunnelwas opened by gcloud.

5. Click Connect.

gcloud

Create an encrypted tunnel to a port of the VM instance:

gcloud compute start-iap-tunnel INSTANCE_NAME INSTANCE_PORT \ --local-host-port=localhost:LOCAL_PORT \ --zone=ZONE

Replace INSTANCE_NAME and INSTANCE_PORT with the nameand port of the VM instance you want to connect to. ReplaceLOCAL_PORT with the localhost port where you want the proxy to bebound. Replace ZONE with the zone where the VM instance islocated.

gcloud performs a connectivity test with the VM instance, then opens atunnel and shows a port number.

Listening on port [LOCAL_PORT].

All traffic sent to localhost:LOCAL_PORT is forwarded to the VMinstance. The port is only accessible by applications running on your localcomputer.

Linux

To install NumPy using pip in Unix platforms, run the following command in a new terminal instance:

$(gcloud info --format="value(basic.python_location)") -m pip install numpy

If the error message persists after installing NumPy, complete the following step:Run the following command to allow gcloud to access external packages:

export CLOUDSDK_PYTHON_SITEPACKAGES=1

Windows

To install NumPy using pip in Windows platforms, run the following command in a new PowerShell instance:

start (gcloud info --format="value(basic.python_location)") "-m pip install numpy"

If the message still persists after installing NumPy, another step is necessary.Run the following command to allow gcloud to access external packages:

$env:CLOUDSDK_PYTHON_SITEPACKAGES="1"