mirror of
https://github.com/angristan/openvpn-install.git
synced 2025-12-16 17:07:02 +01:00
feat: flexible IPv4/IPv6 support with independent endpoint and client addressing (#1419)
## Summary Comprehensive IPv4/IPv6 overhaul that decouples server endpoint addressing from client tunnel addressing, supporting all combinations with automatic leak prevention. ### Supported Configurations | Endpoint | Client Mode | Description | |----------|-------------|-------------| | IPv4 | IPv4-only | Traditional setup (4→4) | | IPv4 | Dual-stack | IPv4 endpoint, clients get both (4→4/6) | | IPv4 | IPv6-only | IPv4 endpoint, clients get IPv6 only (4→6) | | IPv6 | IPv4-only | IPv6 endpoint, clients get IPv4 only (6→4) | | IPv6 | Dual-stack | IPv6 endpoint, clients get both (6→4/6) | | IPv6 | IPv6-only | Full IPv6 setup (6→6) | ### Leak Prevention - **IPv4-only mode**: Pushes `block-ipv6` to clients, blocking all IPv6 traffic - **IPv6-only mode**: Assigns IPv4 addresses and pushes `redirect-gateway def1` to capture IPv4 traffic, which is then dropped (no IPv4 NAT configured) - **Dual-stack mode**: Both protocols tunneled normally ### New CLI Options ``` Network Options: --endpoint-type <4|6> Endpoint IP version (default: 4) --client-ipv4 Enable IPv4 for VPN clients (default: enabled) --no-client-ipv4 Disable IPv4 for VPN clients --client-ipv6 Enable IPv6 for VPN clients (default: disabled) --no-client-ipv6 Disable IPv6 for VPN clients --subnet-ipv4 <x.x.x.0> IPv4 VPN subnet (default: 10.8.0.0) --subnet-ipv6 <prefix> IPv6 VPN subnet (default: fd42:42:42:42::) ``` ### Usage Examples ```bash # Dual-stack clients (IPv4 + IPv6) ./openvpn-install.sh install --client-ipv4 --client-ipv6 # IPv6-only clients (IPv4 traffic blocked) ./openvpn-install.sh install --no-client-ipv4 --client-ipv6 # IPv4-only clients (IPv6 traffic blocked) - default behavior ./openvpn-install.sh install --client-ipv4 --no-client-ipv6 # IPv6 server endpoint ./openvpn-install.sh install --endpoint-type 6 --endpoint 2001:db8::1 # Custom subnets ./openvpn-install.sh install --client-ipv6 --subnet-ipv4 10.9.0.0 --subnet-ipv6 fd00🔢5678:: ``` ### Implementation Details **Core changes:** - New `ENDPOINT_TYPE` variable (4 or 6) controls server listening protocol - New `CLIENT_IPV4`/`CLIENT_IPV6` variables control client tunnel addressing - Renamed `VPN_SUBNET` → `VPN_SUBNET_IPV4`, added `VPN_SUBNET_IPV6` - Separate `resolvePublicIPv4()` and `resolvePublicIPv6()` functions - New `validate_subnet_ipv6()` for ULA (fd00::/8) validation **Protocol handling:** - Uses `proto udp6`/`tcp6` when endpoint type is IPv6 - Firewall and SELinux commands handle both protocol variants **Firewall updates:** - firewalld: Conditional IPv6 masquerade and forwarding - nftables: Separate ip/ip6 tables for NAT based on client config - iptables: ip6tables rules only when IPv6 clients enabled **DNS configuration:** - Unbound listens on IPv4/IPv6 gateway addresses as needed - All third-party DNS providers now include IPv6 servers: - Cloudflare: 2606:4700:4700::1111 - Quad9: 2620:fe::fe - Google: 2001:4860:4860::8888 - OpenDNS: 2620:119:35::35 - AdGuard: 2a10:50c0::ad1:ff **CI/Testing:** - Added `ubuntu-24.04-dual-stack` test matrix entry - Docker test container enables IPv6 forwarding - `CLIENT_IPV6` environment variable passed to test container ## Test Plan - [x] Shellcheck passes - [x] CI Docker tests pass (including new dual-stack test) - [x] Manual testing: IPv4-only mode blocks IPv6 traffic - [x] Manual testing: IPv6-only mode blocks IPv4 traffic - [x] Manual testing: Dual-stack mode tunnels both protocols --- Closes #1317 Closes #1288 Closes #1084 Closes #701 Closes #350
This commit is contained in:
Stanislas
11
.github/workflows/docker-test.yml
vendored
11
.github/workflows/docker-test.yml
vendored
@@ -109,6 +109,15 @@ jobs:
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name: tls-crypt-v2
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sig: crypt-v2
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key_file: tls-crypt-v2.key
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# Test IPv6 dual-stack support on Ubuntu
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- os:
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name: ubuntu-24.04-dual-stack
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image: ubuntu:24.04
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client_ipv6: true
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tls:
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name: tls-crypt-v2
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sig: crypt-v2
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key_file: tls-crypt-v2.key
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name: ${{ matrix.os.name }}
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steps:
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@@ -146,6 +155,7 @@ jobs:
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--cgroupns=host \
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--device=/dev/net/tun:/dev/net/tun \
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--sysctl net.ipv4.ip_forward=1 \
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--sysctl net.ipv6.conf.all.forwarding=1 \
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--network vpn-test \
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--ip 172.28.0.10 \
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-v shared-config:/shared \
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@@ -155,6 +165,7 @@ jobs:
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--stop-signal SIGRTMIN+3 \
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-e TLS_SIG=${{ matrix.tls.sig }} \
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-e TLS_KEY_FILE=${{ matrix.tls.key_file }} \
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-e CLIENT_IPV6=${{ matrix.os.client_ipv6 && 'y' || 'n' }} \
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openvpn-server
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- name: Wait for server installation and startup
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31
README.md
31
README.md
@@ -43,7 +43,7 @@ That said, OpenVPN still makes sense when you need:
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- List and monitor connected clients
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- Uses [official OpenVPN repositories](https://community.openvpn.net/openvpn/wiki/OpenvpnSoftwareRepos) when possible for the latest stable releases
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- Firewall rules and forwarding managed seamlessly (native firewalld and nftables support, iptables fallback)
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- Configurable VPN subnet (default: `10.8.0.0/24`)
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- Configurable VPN subnets (IPv4: default `10.8.0.0/24`, IPv6: default `fd42:42:42:42::/112`)
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- Configurable tunnel MTU (default: `1500`)
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- If needed, the script can cleanly remove OpenVPN, including configuration and firewall rules
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- Customisable encryption settings, enhanced default settings (see [Security and Encryption](#security-and-encryption) below)
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@@ -51,7 +51,11 @@ That said, OpenVPN still makes sense when you need:
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- Variety of DNS resolvers to be pushed to the clients
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- Choice to use a self-hosted resolver with Unbound (supports already existing Unbound installations)
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- Choice between TCP and UDP
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- NATed IPv6 support
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- Flexible IPv4/IPv6 support:
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- IPv4 or IPv6 server endpoint (how clients connect)
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- IPv4-only, IPv6-only, or dual-stack clients (VPN addressing and internet access)
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- All combinations supported: 4→4, 4→4/6, 4→6, 6→4, 6→6, 6→4/6
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- Automatic leak prevention: blocks undesired protocol in single-stack modes
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- Unprivileged mode: run as `nobody`/`nogroup`
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- Block DNS leaks on Windows 10
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- Randomised server certificate name
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@@ -249,7 +253,19 @@ The `install` command supports many options for customization:
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./openvpn-install.sh install --cipher AES-256-GCM --cert-type rsa --rsa-bits 4096
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# Custom VPN subnet
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./openvpn-install.sh install --subnet 10.9.0.0
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./openvpn-install.sh install --subnet-ipv4 10.9.0.0
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# Enable dual-stack (IPv4 + IPv6) for clients
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./openvpn-install.sh install --client-ipv4 --client-ipv6
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# IPv6-only clients (no IPv4)
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./openvpn-install.sh install --no-client-ipv4 --client-ipv6
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# IPv6 endpoint (server listens on IPv6, clients connect via IPv6)
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./openvpn-install.sh install --endpoint-type 6 --endpoint 2001:db8::1
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# Custom IPv6 subnet for dual-stack setup
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./openvpn-install.sh install --client-ipv6 --subnet-ipv6 fd00:1234:5678::
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# Skip initial client creation
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./openvpn-install.sh install --no-client
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@@ -267,9 +283,14 @@ The `install` command supports many options for customization:
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**Network Options:**
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- `--endpoint <host>` - Public IP or hostname for clients (default: auto-detected)
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- `--endpoint-type <4|6>` - Endpoint IP version (default: `4`)
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- `--ip <addr>` - Server listening IP (default: auto-detected)
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- `--ipv6` - Enable IPv6 support (default: disabled)
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- `--subnet <x.x.x.0>` - VPN subnet (default: `10.8.0.0`)
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- `--client-ipv4` - Enable IPv4 for VPN clients (default: enabled)
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- `--no-client-ipv4` - Disable IPv4 for VPN clients
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- `--client-ipv6` - Enable IPv6 for VPN clients (default: disabled)
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- `--no-client-ipv6` - Disable IPv6 for VPN clients
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- `--subnet-ipv4 <x.x.x.0>` - IPv4 VPN subnet (default: `10.8.0.0`)
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- `--subnet-ipv6 <prefix>` - IPv6 VPN subnet (default: `fd42:42:42:42::`)
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- `--port <num>` - OpenVPN port (default: `1194`)
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- `--port-random` - Use random port (49152-65535)
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- `--protocol <udp|tcp>` - Protocol (default: `udp`)
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File diff suppressed because it is too large
Load Diff
@@ -26,11 +26,16 @@ cat /shared/client.ovpn
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if [ -f /shared/vpn-config.env ]; then
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# shellcheck source=/dev/null
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source /shared/vpn-config.env
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echo "VPN config loaded: VPN_SUBNET=$VPN_SUBNET, VPN_GATEWAY=$VPN_GATEWAY"
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echo "VPN config loaded: VPN_SUBNET_IPV4=$VPN_SUBNET_IPV4, VPN_GATEWAY=$VPN_GATEWAY"
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if [ "${CLIENT_IPV6:-n}" = "y" ]; then
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# shellcheck disable=SC2153 # Variables are sourced from vpn-config.env
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echo "IPv6 enabled: VPN_SUBNET_IPV6=$VPN_SUBNET_IPV6, VPN_GATEWAY_IPV6=$VPN_GATEWAY_IPV6"
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fi
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else
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echo "WARNING: vpn-config.env not found, using defaults"
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VPN_SUBNET="10.8.0.0"
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VPN_SUBNET_IPV4="10.8.0.0"
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VPN_GATEWAY="10.8.0.1"
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CLIENT_IPV6="n"
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fi
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# Connect to VPN
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@@ -60,24 +65,49 @@ sleep 5
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echo ""
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echo "=== Running connectivity tests ==="
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# Test 1: Check tun0 interface
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echo "Test 1: Checking tun0 interface..."
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# Test 1: Check tun0 interface (IPv4)
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echo "Test 1: Checking tun0 interface (IPv4)..."
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# Extract base of subnet (e.g., "10.9.0" from "10.9.0.0")
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VPN_SUBNET_BASE="${VPN_SUBNET%.*}"
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VPN_SUBNET_BASE="${VPN_SUBNET_IPV4%.*}"
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if ip addr show tun0 | grep -q "$VPN_SUBNET_BASE"; then
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echo "PASS: tun0 interface has correct IP range (${VPN_SUBNET_BASE}.x)"
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echo "PASS: tun0 interface has correct IPv4 range (${VPN_SUBNET_BASE}.x)"
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else
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echo "FAIL: tun0 interface doesn't have expected IP"
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echo "FAIL: tun0 interface doesn't have expected IPv4"
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exit 1
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fi
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# Test 2: Ping VPN gateway (retries indefinitely, relies on job timeout)
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echo "Test 2: Pinging VPN gateway ($VPN_GATEWAY)..."
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# Test 1b: Check tun0 IPv6 address (if IPv6 enabled)
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if [ "${CLIENT_IPV6:-n}" = "y" ]; then
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echo "Test 1b: Checking tun0 interface (IPv6)..."
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# Extract prefix of subnet (e.g., "fd42:42:42:42" from "fd42:42:42:42::")
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VPN_SUBNET_IPV6_PREFIX="${VPN_SUBNET_IPV6%::}"
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if ip -6 addr show tun0 | grep -q "$VPN_SUBNET_IPV6_PREFIX"; then
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echo "PASS: tun0 interface has correct IPv6 range (${VPN_SUBNET_IPV6_PREFIX}::x)"
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else
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echo "FAIL: tun0 interface doesn't have expected IPv6"
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ip -6 addr show tun0
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exit 1
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fi
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fi
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# Test 2: Ping VPN gateway (IPv4) (retries indefinitely, relies on job timeout)
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echo "Test 2: Pinging VPN gateway (IPv4) ($VPN_GATEWAY)..."
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while ! ping -c 3 -W 2 "$VPN_GATEWAY" >/dev/null 2>&1; do
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echo "Ping failed, retrying..."
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sleep 3
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done
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echo "PASS: Can ping VPN gateway"
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echo "PASS: Can ping VPN gateway (IPv4)"
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# Test 2b: Ping VPN gateway (IPv6, if enabled)
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if [ "${CLIENT_IPV6:-n}" = "y" ]; then
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echo "Test 2b: Pinging VPN gateway (IPv6) ($VPN_GATEWAY_IPV6)..."
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if ping6 -c 5 "$VPN_GATEWAY_IPV6"; then
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echo "PASS: Can ping VPN gateway (IPv6)"
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else
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echo "FAIL: Cannot ping VPN gateway (IPv6)"
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exit 1
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fi
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fi
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# Test 3: DNS resolution through Unbound
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echo "Test 3: Testing DNS resolution via Unbound ($VPN_GATEWAY)..."
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@@ -14,12 +14,22 @@ echo "TUN device ready"
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# Configuration for install
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export FORCE_COLOR=1
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VPN_SUBNET=10.9.0.0 # Custom subnet to test configurability
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VPN_SUBNET_IPV4=10.9.0.0 # Custom subnet to test configurability
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# Calculate VPN gateway from subnet (first usable IP)
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VPN_GATEWAY="${VPN_SUBNET%.*}.1"
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VPN_GATEWAY="${VPN_SUBNET_IPV4%.*}.1"
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export VPN_GATEWAY
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# IPv6 configuration (optional)
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# CLIENT_IPV6: y/n to enable IPv6 for VPN clients
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# VPN_SUBNET_IPV6: IPv6 subnet (ULA prefix, e.g., fd42:42:42:42::)
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CLIENT_IPV6="${CLIENT_IPV6:-n}"
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VPN_SUBNET_IPV6="${VPN_SUBNET_IPV6:-fd42:42:42:42::}"
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# Calculate IPv6 gateway from subnet
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VPN_GATEWAY_IPV6="${VPN_SUBNET_IPV6}1"
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export VPN_GATEWAY_IPV6
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# TLS key type configuration (default: tls-crypt-v2)
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# TLS_SIG: crypt-v2, crypt, auth
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# TLS_KEY_FILE: the expected key file name for verification
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@@ -36,10 +46,17 @@ TLS13_CIPHERSUITES="${TLS13_CIPHERSUITES:-TLS_AES_256_GCM_SHA384:TLS_AES_128_GCM
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INSTALL_CMD=(/opt/openvpn-install.sh install)
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INSTALL_CMD+=(--endpoint openvpn-server)
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INSTALL_CMD+=(--dns unbound)
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INSTALL_CMD+=(--subnet "$VPN_SUBNET")
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INSTALL_CMD+=(--subnet-ipv4 "$VPN_SUBNET_IPV4")
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INSTALL_CMD+=(--mtu 1400)
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INSTALL_CMD+=(--client testclient)
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# Add IPv6 client support if enabled
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if [ "$CLIENT_IPV6" = "y" ]; then
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INSTALL_CMD+=(--client-ipv6)
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INSTALL_CMD+=(--subnet-ipv6 "$VPN_SUBNET_IPV6")
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echo "Testing with IPv6 client support enabled (subnet: $VPN_SUBNET_IPV6)"
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fi
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# Add TLS signature mode if non-default
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if [ "$TLS_SIG" != "crypt-v2" ]; then
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INSTALL_CMD+=(--tls-sig "$TLS_SIG")
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@@ -147,8 +164,13 @@ sed -i 's/^remote .*/remote openvpn-server 1194/' /shared/client.ovpn
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echo "Client config copied to /shared/client.ovpn"
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# Write VPN network info to shared volume for client tests
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echo "VPN_SUBNET=$VPN_SUBNET" >/shared/vpn-config.env
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echo "VPN_SUBNET_IPV4=$VPN_SUBNET_IPV4" >/shared/vpn-config.env
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echo "VPN_GATEWAY=$VPN_GATEWAY" >>/shared/vpn-config.env
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echo "CLIENT_IPV6=$CLIENT_IPV6" >>/shared/vpn-config.env
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if [ "$CLIENT_IPV6" = "y" ]; then
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echo "VPN_SUBNET_IPV6=$VPN_SUBNET_IPV6" >>/shared/vpn-config.env
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echo "VPN_GATEWAY_IPV6=$VPN_GATEWAY_IPV6" >>/shared/vpn-config.env
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fi
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echo "VPN config written to /shared/vpn-config.env"
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# =====================================================
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@@ -550,7 +572,7 @@ if systemctl is-active --quiet firewalld; then
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exit 1
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fi
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# Verify VPN subnet rich rule exists
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if firewall-cmd --list-rich-rules | grep -q "source address=\"$VPN_SUBNET/24\""; then
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if firewall-cmd --list-rich-rules | grep -q "source address=\"$VPN_SUBNET_IPV4/24\""; then
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echo "PASS: VPN subnet rich rule is configured"
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else
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echo "FAIL: VPN subnet rich rule not found in firewalld"
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@@ -602,14 +624,14 @@ else
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# iptables mode - verify NAT rules
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echo "iptables mode, checking NAT rules..."
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for _ in $(seq 1 10); do
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if iptables -t nat -L POSTROUTING -n | grep -q "$VPN_SUBNET"; then
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echo "PASS: NAT POSTROUTING rule for $VPN_SUBNET/24 exists"
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if iptables -t nat -L POSTROUTING -n | grep -q "$VPN_SUBNET_IPV4"; then
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echo "PASS: NAT POSTROUTING rule for $VPN_SUBNET_IPV4/24 exists"
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break
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fi
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sleep 1
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done
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if ! iptables -t nat -L POSTROUTING -n | grep -q "$VPN_SUBNET"; then
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echo "FAIL: NAT POSTROUTING rule for $VPN_SUBNET/24 not found"
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if ! iptables -t nat -L POSTROUTING -n | grep -q "$VPN_SUBNET_IPV4"; then
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echo "FAIL: NAT POSTROUTING rule for $VPN_SUBNET_IPV4/24 not found"
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echo "Current NAT rules:"
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iptables -t nat -L POSTROUTING -n -v
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systemctl status iptables-openvpn 2>&1 || true
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