Android VPN From Scratch: Client Install, Subscription Import and Battery Settings Guide

Setting up an Android VPN breaks down into five steps: install the client, grant VPN permission, import the subscription, choose routes and split tunneling, and whitelist the app for battery. The five are independent, yet any one going wrong looks identical on the surface — it will not connect — so troubleshooting tends to circle the same spot. Below they are walked through in the order you actually meet them, with a self-check after each, then a verification checklist and a fault table.

Prep: Client Source and Account Check

The C6VPN Android client and your subscription details both come from the user panel; marketing pages never host direct download links. Signing up needs only a username and password — no email address — and the account itself carries no identifying information.

The install source is the first thing to verify. Packages reposted on third-party app sites, chat groups or cloud drives may have been repackaged. Such builds usually keep the icon and name intact but ask at launch for permissions unrelated to their function. There are two checks: take the package only from the download entry inside the panel, and glance at the permission list the system shows before installing — a client whose job is acceleration should not ask for contacts, calendar or call logs on first launch.

On the account side, note two things: the username and password you log in with, and the subscription link generated in the panel. A subscription link is not an ordinary URL — it is the credential the client uses to pull the node list, and you will come back to it during import.

Install and System Permission

On first launch after installing, Android shows a system-level dialog asking whether to allow the app to establish a VPN connection. That dialog is drawn by the system's VpnService framework, not by the app, so its styling varies with the Android version — newer versions spell out that the app will intercept all network traffic on the device. You must tap Allow; only then can a tunnel exist.

If you decline, the app usually shows 'not authorized', and tapping connect again brings the same system dialog back. If the system remembers the refusal and stops showing it, go to Settings → Network & internet → VPN, delete the leftover entry and try again.

Once permission is granted, a persistent icon (a key or a square) appears in the status bar. That is the system telling you a VPN is running, and apps cannot hide it. Some customized ROMs fold it into a notification group, which can look like nothing happened — pull down the notification shade to confirm.

One more limit that is easy to miss: Android lets only one app hold the VPN tunnel at a time. If another acceleration app is installed and connected, or has always-on VPN enabled, the new client cannot get the tunnel. When troubleshooting, first check the system VPN settings to confirm no second app is active.

Import the Subscription Link

The subscription link generated in the panel is a URL with parameters. The client uses it to request a node list from the server, then parses whatever format it supports. Subscription content usually comes in one of three shapes:

• A base64-encoded node string: one node address per line, the whole thing base64-encoded once — the most widely used form;
• YAML config as used by Clash / Mihomo: includes proxy groups and rule sets, suited to clients with a rule engine;
• A JSON structure such as SIP008: standardized fields, easy for programs to read.

Clients differ in what they accept. Most general-purpose Android clients take base64 and SIP008; clients with a rule engine take YAML. Checking the client's format requirements before importing saves far more time than reinstalling repeatedly.

There are three ways to import, ranked by reliability:

1. Clipboard import: copy the full link and choose 'Import from clipboard' in the client. Fewest steps, fewest mistakes.
2. QR code import: generate a QR code for the link in the panel and scan it with the client. Good when the link is long and manual copying tends to drop characters.
3. Manual paste: add a new entry on the subscription management page, paste the link into the field, save, then trigger an update by hand.

The three most common reasons an import fails: the link was truncated by a chat app or mail client and lost its trailing parameters; leading or trailing spaces or a line break came along with the paste; or the link itself has expired or been reset. The first two are fixed by copying the whole thing again; the third means generating a new link in the panel.

Protocols and Routes: Purpose First, Route Type Second

After import the client lists every node. Node names usually carry a region and a route type; understand those two and your pick will be close to right most of the time.

Protocol differences

The protocol decides how data is encapsulated between client and server. Six are common on Android:

A practical trade-off: UDP-based protocols (Hysteria2, TUIC) are usually steadier than TCP-based ones on mobile networks with heavy packet loss, but on networks that rate-limit UDP they do worse. When it connects but the speed will not climb, switching transport layer often helps more than switching region.

Route types

The labels 'dedicated line', 'relay' and 'direct' in node names describe the path data takes from entry to exit:

• Direct: the exit server terminates the connection itself, the shortest path. The cross-border leg runs over the public internet, so peak-hour congestion hits it.
• Relay: you connect first to a nearby relay node, which then carries the traffic abroad. The public-internet leg is shorter, so stability is a notch above direct.
• IEPL dedicated line: end to end over a private link, never touching the public internet. The steadiest latency and packet loss, and the highest cost.

For example, Tokyo IEPL and Singapore IEPL suit long-lived connections that are sensitive to stability, such as video calls and large file sync; Los Angeles relay and London relay beat direct routes for intercontinental access; Hong Kong direct and Seoul direct have the shortest paths and suit interactive work where latency comes first. C6VPN currently covers 110+ countries and 250+ routes, and a single region often offers more than one type — filter by purpose first, then by the region of the site you need.

Split Tunneling and Per-App Proxy

Clients usually offer three modes: global, rule (split tunneling) and direct. Global pushes all traffic into the tunnel; rule mode decides by domain, IP range or GeoIP; direct skips the tunnel entirely.

The point of rule mode is to avoid detours. Send local sites through the tunnel and their traffic leaves the country and comes back, which only adds latency. Most clients ship with common rule sets that use GeoIP to decide which region a destination belongs to, then choose tunnel or direct.

Per-app proxy is one of Android's genuinely useful features: tick only the apps that should use the tunnel and leave the rest direct. It is more thorough than domain rules because the decision is based on the app, not the destination address — ideal when only one app needs cross-border access. One caveat once it is on: an excluded app that relies on the same DNS settings may fail to resolve. If that happens, give that app its own DNS or switch back to global mode to confirm the cause.

DNS is the part of split tunneling that goes wrong most often. In rule mode, if DNS queries go to the local ISP while traffic goes through the tunnel, the resolved address will not match the actual exit — the classic symptom is getting a local CDN node and then dragging that traffic through the tunnel and back. Client DNS settings usually include options such as 'follow proxy' or 'use DNS inside the tunnel'; turn one on so resolution and traffic take the same path.

Battery Whitelist and Background Survival

After the screen has been off for a while, Android enters Doze mode, deferring background network access and limiting wake-ups. Vendor ROMs add a more aggressive layer on top: clearing background apps when the screen locks, restricting autostart, and demoting long-running services. A VPN client needs a resident foreground service to keep the tunnel alive, which makes it exactly the kind of app these policies target.

There are two layers to deal with:

1. System layer: add the client to the 'not optimized' list in battery optimization settings. This is stock Android, present on every device, and takes priority.
2. Vendor layer: in app management, allow 'autostart', 'run in background' and 'keep running after screen lock', and set the battery policy to 'unrestricted'.

Names differ by brand, but they all sit under Settings → Apps → Battery / Permissions. If you cannot find the entry, search for the app name at the top of system settings; that usually jumps straight to the battery policy page. Xiaomi's battery saver, Huawei's app launch management, OPPO and vivo's autostart and background running, Samsung's background usage limits — they are all the same kind of switch.

One more detail: some systems have a 'keep Wi-Fi on during sleep' switch. With it off, Wi-Fi drops when the screen goes dark and the tunnel has to be rebuilt. Turn it on for long downloads or syncs. If you would rather not configure every app, a middle path is to check the whitelist only before sessions that need a long connection (calls, downloads, remote desktop) and leave system settings alone for short everyday use.

Verify: Three Checks That the Tunnel Works

The client showing 'connected' only means the local tunnel came up; it does not mean traffic actually leaves through the exit you expect. Work through the following:

• ✅ An IP lookup page shows an exit IP matching the region of the node you picked
• ✅ The ISP or ASN in the result belongs to that region, not to your local provider
• ✅ The resolvers listed by a DNS leak test sit inside the tunnel
• ✅ A browser WebRTC test does not expose your local network address
• ✅ The app or site you need opens normally, with acceptable response times
• ❌ The exit IP still belongs to your local ISP → the tunnel is not up, or a split-tunnel rule classified this traffic as direct
• ❌ The resolvers belong to your local ISP → DNS queries are not going through the tunnel
• ❌ Only some apps are affected → check the per-app proxy list, and whether that app is going out over IPv6 directly

Of these, the IP and DNS checks tell you the most. IP right but DNS wrong shows up as some sites failing to open or loading slowly; DNS right but IP wrong means the tunnel never took over the traffic at all, so go back to permissions and mode settings.

Six Common Faults at a Glance

Here is a table of the failure points that keep coming up above; when something breaks, find the row by symptom:

Long-Term Use: Updates, Switching and Billing Rules

Subscription content changes as routes are adjusted, so updating it regularly keeps the node list current. Clients usually have an 'update subscription' button, and the subscription management page may let you set an automatic update interval. If an update fails, first confirm the link has not expired, then confirm the network itself is up — updating with the tunnel disconnected is sometimes smoother.

Keeping exactly one VPN app active is the easiest way to cut down on sudden connection failures. With several similar apps installed, the system VPN settings accumulate profiles; removing the ones you do not use prevents them from competing for the tunnel.

A few billing rules are worth knowing up front: C6VPN's monthly plan resets its data allowance on the same day each month, and upgrading mid-cycle converts the price difference into remaining days; data packs last until used up and never expire, which suits irregular usage; simultaneous devices are unlimited; payment accepts Alipay, WeChat Pay and USDT; and a full no-questions refund can be requested within 30 days of the first payment. These rules affect the real experience more than the unit price does — especially when usage swings, where a data pack often works out cheaper than a monthly plan.