# Sentry Tunnel General Setup

The setup process does require the users to have some knowledge regard networking to effectively trouble shoot any issues that comes up. To help you better visualize the process, we have provided steps by steps guide on how to setup TCPShield VXLAN for Bedrock, FiveM and rAtherna (Ragnarok) servers, with other type of services coming soon.

[rAthena/Ragnarok](/vxlan/sentry-tunnel-for-rathena-ragnarok.md) 

[Bedrock/Geyser.](/vxlan/sentry-tunnel-for-bedrock-geyser-pocketmine-voicechat.md)

[FiveM/GTA Online.](/vxlan/sentry-tunnel-for-fivem-gta-online.md)\
\
Keep in mind that the setup process is pretty much the same across all applications. But if you run into issues along the way, please head to our Discord channel and open a ticket.

### Before you begin:

**a. Basic requirements**

* **Root access (or full sudo) on a Linux server** so you can create/manage network interfaces, routes, and firewall rules.
* A server environment where you’re allowed to use kernel networking features (VXLAN is a Linux networking feature, and Sentry Tunnel is UDP-based).

**b. Who likely can’t use it**

* **Shared hosting / managed game hosting** where you *don’t* have root access or are blocked from creating custom network interfaces. (In those setups, you typically can’t bring up a VXLAN interface at all.)

**c. What about Windows Server?**

* You *can* still protect a Windows-hosted service, but it’s usually **more complicated**: you’ll typically run a **Linux proxy in front** (VPS or dedicated) to terminate the VXLAN tunnel and then forward traffic to the Windows server. This adds an extra component/hop and extra routing rules compared to a direct Linux origin.

## 1. Tunnel Creation

Head to our dashboard and navigate to the Tunnels section on the left corner, then click on New Tunnel:

<figure><img src="/files/ngsaUZmdFYKxWR6O12PE" alt=""><figcaption></figcaption></figure>

You’ll see the following fields:

1. **Name**: A custom label for your tunnel, use something descriptive.
2. **Endpoint**: The external IP address of your backend server (e.g., your VPS or physical machine). This is where the VXLAN tunnel will forward traffic.

<details>

<summary>Protecting multiple ports</summary>

Since VXLAN tunnel doesn't care which port your service is running on (port-agnostic), the Endpoint should only contains your backend IPv4.

Hence you can have multiple services / gameserves being protected behind a single Tunnel instance, which is very useful for scalability.&#x20;

</details>

1. **Locations**: The location will always be Anycast for optimal global routing.
2. **Port**: A port will be automatically assigned from the range 32768–60999. This is the port our VXLAN tunnel will use to communicate with your backend. No need to change this unless you have specific routing or firewall requirements.&#x20;

<details>

<summary>VXLAN PORT</summary>

<mark style="color:purple;">This assigned port is</mark> <mark style="color:purple;"></mark><mark style="color:purple;">**NOT**</mark> <mark style="color:purple;"></mark><mark style="color:purple;">your service port (e.g.,</mark> <mark style="color:purple;"></mark><mark style="color:purple;">**6900**</mark> <mark style="color:purple;"></mark><mark style="color:purple;">for Ragnarok or</mark> <mark style="color:purple;"></mark><mark style="color:purple;">**25565**</mark> <mark style="color:purple;"></mark><mark style="color:purple;">for Minecraft). Your application will continue to listen on its usual port. The VXLAN tunnel just forwards traffic to that original port via the backend IP.</mark>&#x20;

</details>

<figure><img src="/files/2d7sSjy4KFeWFGddtikQ" alt=""><figcaption><p>Tunnel creation</p></figcaption></figure>

## 2. Tunnels Overview

Once the tunnel is created, you'll be redirected to the Overview page, which will show all of the necessary information:

<figure><img src="/files/XhNNet4DoK38mSZIlIsd" alt=""><figcaption><p>Tunnel Overview Page</p></figcaption></figure>

* **Public IP**: The dedicated IP your users will connect to (e.g., 104.234.6.152).
* **Private IP**: An internal VXLAN address (e.g., 172.18.152.2) used for routing within the overlay network.

<details>

<summary><strong>Why does VXLAN use private IPs like 172.18.x.x</strong>? </summary>

These are reserved for internal overlay communication, which keeps them isolated from the public internet while enabling full bidirectional routing between nodes in your VXLAN environment.

</details>

* **VXLAN Port**: The port assigned for VXLAN traffic (e.g., 33154).
* **Endpoint**: The backend IP of your game or application server.  You can change this value whenever you like, but make sure to also re-run the Setup Script when you do so.&#x20;

<details>

<summary>Changing your Endpoint Settings:</summary>

Once you have updated your backend IPv4, the page should refresh and you will see a new Setup Script being generated.

</details>

* **Setup Scrip**t: At the bottom of the Overview page, you’ll find a Setup Script that looks like this.&#x20;

```
grep -q tunnel_table /etc/iproute2/rt_tables || echo "200 tunnel_table" >> /etc/iproute2/rt_tables;
ip rule | grep -q "tunnel_table" || ip rule add fwmark 9 table 200
ip link add vxlan_214 type vxlan id 214 remote 198.178.119.30 dstport 33154;
ip link set dev vxlan_214 address 12:cc:6c:3d:95:b6;
ip neigh add 172.18.152.2 lladdr 12:dd:6c:3d:95:b6 dev vxlan_214 nud permanent;
ip link set dev vxlan_214 mtu 1450;
ip addr add 172.18.152.3/24 dev vxlan_214;
ip link set vxlan_214 up
ip route add default via 172.18.152.2 dev vxlan_214 table 200
sysctl -w net.ipv4.conf.vxlan_214.rp_filter=0
ip addr add dev lo 104.234.6.152/32
iptables -t mangle -I OUTPUT -s 104.234.6.152/32 -j MARK --set-xmark 0x9
iptables -t mangle -A POSTROUTING -s 104.234.6.152/32 -j MARK --set-mark 0
```

We'll include explanation for each line in the script for anyone interested:

{% tabs %}
{% tab title="1. 2." %}
`grep -q tunnel_table /etc/iproute2/rt_tables || echo "200 tunnel_table" >> /etc/iproute2/rt_tables;`&#x20;

Ensures that a custom routing table named `tunnel_table` with ID `200` exists in `/etc/iproute2/rt_tables`.&#x20;

`ip rule | grep -q "tunnel_table" || ip rule add fwmark 9 table 200`&#x20;

Adds rule to route packets marked with firewall mark `9` (`fwmark 9`) using the custom routing table `200`. This allows selectively routing marked packets through the VXLAN tunnel
{% endtab %}

{% tab title="3. 4." %}
&#x20;`ip link add vxlan_214 type vxlan id 214 remote 198.178.119.30 dstport 33154;`&#x20;

Creates a VXLAN interface named `vxlan_214` with:

* **VXLAN ID** `214`
* **Remote IP** `198.178.119.30`&#x20;
* **Destination UDP port** `33154` (VXLAN usually uses UDP)

`ip link set dev vxlan_214 address 12:cc:6c:3d:95:b6;`&#x20;

Assigns a custom MAC address `12:cc:6c:3d:95:b6` to the VXLAN interface.
{% endtab %}

{% tab title="5. 6. 7. 8. 9." %}
&#x20;`ip neigh add 172.18.152.2 lladdr 12:dd:6c:3d:95:b6 dev vxlan_214 nud permanent;`&#x20;

Adds a static (permanent) ARP entry: **IP** `172.18.152.2` → **MAC** `12:dd:6c:3d:95:b6` . This ensures the system knows how to reach the remote endpoint inside the tunnel, bypassing ARP resolution. You can use [arping](https://docs.tcpshield.com/vxlan/common-issues-and-debugging#id-1.2.-interface-traffic) to verify interface traffic coming from VXLAN public & private IP address to confirm whether the virtual link is properly resolving IP-to-MAC.

`ip link set dev vxlan_214 mtu 1450;`&#x20;

Sets the Maximum Transmission Unit of the VXLAN interface to `1450`. VXLAN adds \~50 bytes of overhead; this avoids fragmentation (standard MTU is 1500).

`ip addr add 172.18.152.3/24 dev vxlan_214;`&#x20;

Assigns the local tunnel IP address `172.18.152.3` to the VXLAN interface.

`ip link set vxlan_214 up` \
Brings up the VXLAN interface. You can replace `up` with `down` to shutdown the interface if needed.

&#x20;`ip route add default via 172.18.152.2 dev vxlan_214 table 200`&#x20;

In routing table `200`, sets the default route to go through the remote endpoint `172.18.152.2` using `vxlan_214`.
{% endtab %}

{% tab title="10. 11. 12. 13." %}
`sysctl -w net.ipv4.conf.vxlan_214.rp_filter=0`&#x20;

Validates incoming packets are arriving on vxlan\_214 interface -​​ by verifying their source address against the routing table.

`ip addr add dev lo 104.234.6.152/32`&#x20;

Adds the public IP `104.234.6.152` as a loopback alias on the local system. This is why when pinging, you should see <1ms response time.

`iptables -t mangle -I OUTPUT -s 104.234.6.152/32 -j MARK --set-xmark 0x9`&#x20;

Marks packets **originating from** `104.234.6.152` with mark `9` in the mangle table (`fwmark 9`). This mark is used by the earlier `ip rule` to route traffic through the VXLAN tunnel.

`iptables -t mangle -A POSTROUTING -s 104.234.6.152/32 -j MARK --set-mark 0`&#x20;

After routing, unsets the firewall mark (reset to `0`) in the `POSTROUTING` chain. Ensures that the mark doesn’t leak into other parts of the system or confuse other ip rules or NAT.
{% endtab %}
{% endtabs %}

## 3. Firewall configuration:

Most cloud providers have a firewall enabled by default. To make sure your backend works correctly, please follow the steps in our guide (linked below) to allow the necessary ports. If you’re not sure how to do this, you can also check your cloud provider’s help articles or look up guides for `ufw` or `iptables`.

<https://docs.tcpshield.com/vxlan/common-issues-and-debugging#id-1.3-firewall-configuration>

For customers using <mark style="color:blue;">Pterodactyl</mark>, ensure that you open the VXLAN port on the panel itself. This can be done by navigating to the **Network** tab and selecting **Create Allocation**. For more information, visit this [guide](https://knowledgebase.aquatis.host/books/pterodactyl-guides/page/how-do-i-addopen-a-server-port-on-pterodactyl).

## 4. Setting up Sentry Tunnel:

Copy and run your Setup Script. Pasting it directly in the terminal should be fine, or you can create a custom `.sh` script in case you need to re-run it later.&#x20;

You can verify that the tunnel was created by running:

```
ip -s link show vxlan_214
```

Example output:

```
root@admin:~# ip -s link show vxlan_214
472: vxlan_214: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000
    link/ether 12:cc:6c:3d:95:b6 brd ff:ff:ff:ff:ff:ff
    RX: bytes  packets  errors  dropped missed  mcast   
    0          0        0       0       0       0       
    TX: bytes  packets  errors  dropped carrier collsns 
    648        7        0       0       0       0       
```

And with it:

* Your server will now be reachable via the assigned public IP. For example, your TeamSpeak server is reachable via `104.234.6.152:9987` or your Lineage server via `104.234.6.152:2160`  etc etc.
* You can also head to our [Setup Checklist](https://docs.tcpshield.com/vxlan/common-issues-and-debugging#id-1.-vxlan-setup-check-list) page to verify your setup. If  run into any issue along the way, either head to our [Debugging Page](/vxlan/common-issues-and-debugging.md) or make a ticket on our [Discord](https://discord.com/invite/tcpshield) channel.

### 5. Recommend: Configure our ProtoGuard Firewall:

On our Sentry tunnel we have developed strict mitigation for selected games and services,imply head to our Firewall Tab to enable them:

**Fitler Name**: You can select the desired protocol here. Traffic that does not conform to said protocol will be dropped. At the moment we offer ProtoGuard Firewall for:

* FiveM&#x20;
* Simple Voice Chat
* Minecraft Bedrock/Geyser
* ARK Survival Evolved
* Counterstrike: Global Offensive (including CS2)
* Rust
* TeamSpeak
* Valheim

With more coming later.\
**Start Port/End Port**: You can insert port range where the filter would apply,&#x20;

<div data-full-width="true"><figure><img src="/files/S4asw7gCiSvDPHXayfy6" alt="" width="525"><figcaption><p>Firewall Selection Page</p></figcaption></figure></div>


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