Setting up secure traffic routing across cloud infrastructure doesn't have to be an uphill battle. When you configure a Google Cloud Platform proxy, you control how external requests enter your virtual private cloud, protect backend services from common web vulnerabilities, and manage high-volume workloads without downtime.
If you're building distributed applications or managing private subnets that require secure internet egress or ingress, standard load balancers won't always cut it. You need a dedicated proxy architecture. This guide walks through the exact steps, configurations, and network topologies required to deploy and maintain proxy solutions inside Google Cloud.
Understanding Google Cloud Proxy Architecture
Google Cloud handles traffic routing through several distinct proxy mechanisms depending on whether you're managing ingress or egress traffic. Unlike traditional on-premise reverse proxies that require manual server provisioning, GCP utilizes distributed software-based proxy layers integrated directly into its software-defined networking stack.
Ingress Versus Egress Proxies
- Ingress Proxies: These sit at the edge of your network, terminating incoming client connections before forwarding traffic to backend instances, container clusters, or serverless functions.
- Egress Proxies: These manage outbound traffic from private internal instances to external APIs or services, enabling strict IP whitelisting and egress filtering.
Global external HTTP(S) load balancers, for instance, rely on distributed Envoy proxies deployed at Google's network edge. This means traffic is intercepted close to the user before traversing Google's private global backbone network.
Core Setup Steps for Google Cloud Proxy
Deploying a custom forwarding proxy or configuring native managed proxy services requires careful adherence to networking prerequisites. Here's how to build a secure proxy instance using a Compute Engine virtual machine running Squid or Envoy, or by setting up native HTTP(S) load balancing proxies.
Step 1: Provision the Network Environment
Before launching any proxy instance, configure a custom Virtual Private Cloud (VPC) network with distinct public and private subnets.
- Navigate to the VPC networks section in the Google Cloud Console.
- Click Create VPC Network, name your network, and choose custom subnet mode.
- Define a public subnet (for the proxy ingress point) and a private subnet (for backend applications that shouldn't have direct public IPs).
- Set up appropriate firewall rules to allow incoming traffic on ports 80 and 443 for public-facing proxies, while blocking direct inbound access to private subnet instances.
Step 2: Deploy and Configure the Proxy Instance
If you're running a self-managed forward or reverse proxy on Compute Engine:
- Launch a minimal Linux instance (such as Debian or Ubuntu) inside your public subnet.
- Assign a static external IP address to the instance if it needs to serve as an entry point, or keep it internal if it functions as an egress proxy.
- Install your proxy software of choice. For an HTTP/HTTPS forward proxy, Squid is a common choice. For microservices and advanced routing, Envoy is preferred.
- Update your configuration file to define allowed source IP ranges. For example, in a Squid configuration, restrict access so only internal VMs can route traffic through it:
acl internal_subnet src 10.0.1.0/24
http_access allow internal_subnet
http_access deny all
http_port 3128
Step 3: Configure Route Tables and Firewalls
To direct traffic from private instances through your newly created egress proxy:
- Create a custom route in your VPC pointing default traffic (0.0.0.0/0) or specific destination ranges to the internal IP address of your proxy virtual machine.
- Ensure IP forwarding is enabled on the proxy instance's network interface so it can accept packets destined for external addresses.
- Test connectivity from a private instance using curl to verify that outbound requests pass through the proxy correctly.
Advanced Traffic Management and Security Controls
Production environments demand more than basic packet forwarding. To keep your infrastructure secure, implement these advanced controls.
SSL/TLS Termination
Terminating SSL at the proxy layer offloads cryptographic overhead from backend application servers. When using Google's managed HTTPS load balancers, you upload your SSL certificates directly to Certificate Manager. For self-managed proxies, store private keys securely using Secret Manager rather than baking them directly into instance disks.
Access Control Lists and IAM
Restrict who can modify proxy configurations by applying strict Identity and Access Management roles. Grant Compute Network Admin permissions only to senior platform engineers, and use service accounts with minimal scopes for any automated proxy deployment scripts.
Common Configuration Mistakes to Avoid
Even experienced engineers run into roadblocks when configuring cloud proxies. Watch out for these pitfalls:
- Forgetting IP Forwarding: If you deploy a custom VM-based router or proxy without enabling IP forwarding in the GCP console, packets will drop silently.
- Misconfigured Firewall Tags: Forgetting to apply network tags to firewall rules can leave your proxy wide open to the public internet or block internal traffic entirely.
- Ignoring Connection Timeouts: Default TCP timeout settings on cloud load balancers can drop long-lived WebSocket or database connections prematurely. Adjust timeout values based on your application requirements.
Frequently Asked Questions
What is the difference between a Google Cloud HTTP(S) Load Balancer and a custom proxy VM?
Managed HTTP(S) load balancers use Google's globally distributed Envoy proxy infrastructure automatically, requiring zero server maintenance. A custom proxy VM gives you total control over routing rules and software configuration, but you are responsible for patching, scaling, and uptime.
How do I restrict outbound traffic from private VMs using a proxy?
You can route all outbound traffic from private subnets through an internal TCP/UDP load balancer backed by a pool of proxy instances running Squid or Tinyproxy, combined with firewall rules that block direct internet access for all other instances.
Can I inspect encrypted HTTPS traffic passing through a GCP proxy?
Yes, but only if you configure SSL termination at the proxy layer using valid certificates. End-to-end encryption (where the proxy passes raw TLS streams without decryption) prevents inspection unless client certificates are installed on the proxy itself.
How does autoscaling work with managed proxy instances?
Managed proxy services scale automatically based on request volume and CPU utilization. For custom VM-based proxies, you must place them behind a managed instance group and configure autoscaling policies based on network throughput or CPU metrics.
