The Competition Dimension of Network Tunneling Has Changed: Some Are Still Fiddling with Port Forwarding, While Others Are Letting AI Build Tunnels Itself

title: "The Competition Dimension of Network Tunneling Has Changed: Some Are Still Fiddling with Port Forwarding, While Others Are Letting AI Build Tunnels Itself" description: "From ngrok to Cloudflare Tunnel to Sealtun, network tunneling tools are undergoing a paradigm shift—not just exposing localhost to the public, but enabling AI agents to complete the entire connection from local to public network, from machine to cluster." tags: ["Network Tunneling", "Sealtun", "Sealos", "ngrok", "Cloudflare Tunnel", "Kubernetes", "AI Programming"]

Have you ever seen a symphony orchestra with only one musician?

For most developers today, network tunneling is exactly that state—you manually type a command, manually copy the link, manually send it to a colleague, manually check if the tunnel is broken, and manually restart it. Every step requires human intervention.

What's more ironic is that AI can already write and run your application, elegantly outputting Local: http://localhost:3000 in the terminal. Then what? You still have to act as half a sysadmin: find a server, configure Nginx, apply for certificates, open security groups, modify firewall rules.

AI writes the code, but you still have to run the last 100 meters of network connectivity yourself.

This contradiction is being resolved by a new tool—not a faster ngrok, but Sealtun, which places tunneling back into the Kubernetes workflow.

From "Can You Access Me" to "Can It Connect Itself"

The evolution of network tunneling tools has roughly gone through three stages:

Phase 1: Manual Tunneling. The era of frp and ngrok. You can use them, but every step requires manual effort—install the client, write configuration, start the service, copy the link. The free version of ngrok changes domain on every restart, making it unusable for production.

Phase 2: Platform‑Managed. The era of Cloudflare Tunnel. It's free, stable, and comes with built‑in Zero Trust security, but you need to host your domain on Cloudflare, configure the cloudflared client, and write ingress rules. It's powerful, but it's a tool within Cloudflare's ecosystem, not part of your development workflow.

Phase 3: Workflow‑Embedded. The direction represented by Sealtun. It is not just a tunneling tool, but a part of the Sealos Cloud and Kubernetes workflow. Login with your Sealos account, certificates are automatically issued, Ingress is auto‑configured, and Pod status, Service status, logs, and events are all in the same context.

This is not a feature upgrade but a paradigm shift: The tunnel changes from 'an extra tool I install' to 'a step in my workflow'.

Two Commands, Two Directions

Sealtun has only two core capabilities, but they cover the two most painful directions for developers:

Direction 1: Push local services to the public network.

sealtun login
sealtun expose 3000

One command gives you an HTTPS URL. Share it with colleagues, fill it into a Webhook callback URL, or let another AI Agent continue joint debugging.

What it saves is not the 'can it tunnel' issue—ngrok can do that too. What it saves is all the work after tunneling: no need to configure Nginx reverse proxy, no manual certificate application, no security group setup, no need to explain what localhost is to non‑technical colleagues.

Direction 2: Pull cluster services to your local machine.

sealtun login
sealtun connect --check
sudo sealtun connect

After startup, your local machine can directly access Service FQDN, ClusterIP, and Pod IP in the Kubernetes cluster. MySQL, Redis, curl, browser, local debugging tools—none need separate proxy configuration.

Previously, to access a service in the cluster from your local machine, the common practice was kubectl port-forward, which can only forward one port at a time and disconnects frequently. Sealtun's connect uses transparent TCP mode, temporarily writing to iptables and /etc/hosts, allowing all tools to access seamlessly.

One pushes out, one pulls back. Two directions, one tunnel.

Sharing a Link ≠ Exposing a Public Link

What are you most afraid of with temporary previews? Afraid the link will be forwarded, afraid you'll forget to turn it off, afraid anyone with the link can access it.

Sealtun's security controls are not patches after the fact, but built‑in capabilities:

• Basic Auth
• Bearer Token
• IP whitelist/blacklist
• Rate limiting
• Temporary share links (automatically expire after 1 hour, with rotation support)
• Access audit (records of who accessed what and when)

You don't need to learn all these capabilities at once, but when 'send it to someone for a quick look' becomes a real workflow, access control and revocability must keep up.

A share link without an expiration mechanism is a ticking time bomb.

Be Aware of the Costs: Sealtun Is Not a Panacea

Every tool has its boundaries, and Sealtun is no exception. Before deciding to use it, you need to know these:

1. It is tied to the Sealos ecosystem. Sealtun's login, certificates, Ingress, and diagnostics all depend on Sealos Cloud. If you don't use Sealos, Sealtun is meaningless to you. This is not a general‑purpose tool, but an ecosystem tool.

2. The connect feature is Linux‑only. Transparent TCP mode requires writing to iptables and /etc/hosts; macOS and Windows are explicitly not supported yet. If you are a Mac developer, you can only use the expose direction.

3. The project is still very early. On GitHub, it has 61 stars, 8 forks, 0 issues, 0 PRs, and no License set. This means low community engagement; documentation and stability still need time to be verified. Use with caution in production.

4. Costs come from Sealos Cloud. Sealtun itself is free, but the CPU, memory, ports, and traffic consumed by the tunnel are billed through Sealos Cloud. Unit prices vary by region; if you keep the tunnel running indefinitely, the bill will tell the story.

5. Requires root privileges. The connect mode requires sudo, which may be an obstacle in containerized development environments.

Competitive Comparison: Which One Should You Use?

Recommendation:

• If you only need to quickly show a page to a colleague → ngrok is sufficient
• If you need long‑term stable exposure and your domain is on Cloudflare → Cloudflare Tunnel
• If you want full control and have server resources → frp
• If you use Sealos Cloud or Kubernetes and need two‑way access between cluster and local → Sealtun

Tunnels in the AI Agent Era Should Be Agent‑Friendly

The most interesting design of Sealtun is not the technology itself, but the Skill prepared for Codex.

npx skills add https://github.com/gitlayzer/sealtun

After installation, when you say in Codex 'expose local port 3000', the AI doesn't need to guess commands from scratch or flip through the README. It knows to use Sealtun, knows to check login status first, knows when to give advice only without executing, and knows that state‑changing commands like expose, apply, stop need extra caution.

This is not about making AI memorize a few commands, but about making AI better understand the boundaries of operations.

This approach is worth learning for all CLI tools: In the era of AI programming, command‑line tools must not only be human‑friendly, but also agent‑friendly. If your tool cannot be used by AI, then after AI writes the code for the user, the user still has to look up the documentation and type commands themselves—the efficiency gain of AI programming is lost in the last 100 meters.

Trend Assessment

The competitive dimensions of network tunneling tools are changing:

In the past, it was about: who is faster, who is more stable, who offers more free quota.

In the future, it's about: who understands your workflow better, who can let AI complete the tunneling itself, and who can turn the tunnel from an 'extra tool' into a 'step in the workflow'.

Sealtun is still very early, with a 61‑star project still far from production‑ready. But the direction it points to is correct: a tunnel should not be a standalone tool, but a native capability of the development platform.

Just like before the iPhone, browsing the internet on a phone required installing an extra browser, email client, and map app. The iPhone turned these into native capabilities. What Sealtun is doing is similar—turning network tunneling from 'an extra tool you install' into 'a platform‑native step'.

This direction is far more important than supporting an additional protocol or opening one more node.

Sealtun project address: https://github.com/gitlayzer/sealtun

Sealos China cluster: https://cloud.sealos.run

If you are often interrupted by issues like localhost sharing, Webhook callbacks, or debugging cluster services locally, give it a try. But remember: it's tied to the Sealos ecosystem, the connect feature only supports Linux, and the project is still early. Before choosing a tool, first understand the costs.