Karavi at 19:42, 21 June 2026

2026-06-21T19:42:44Z

← Older revision		Revision as of 19:42, 21 June 2026
Line 10:		Line 10:
	\| '''Device''' \|\| Ubuntu 24.04 \|\| MikroTik RouterOS 7.20+		\| '''Device''' \|\| Ubuntu 24.04 \|\| MikroTik RouterOS 7.20+
	\|-		\|-
	\| '''Public IP''' \|\| 157.90.26.4 \|\| 78.~~157~~.42.~~222~~		\| '''Public IP''' \|\| 157.9.2.4 \|\| 85.57.4.221
	\|-		\|-
	\| '''Tunnel IP''' \|\| 10.0.0.1/30 \|\| 10.0.0.2/30		\| '''Tunnel IP''' \|\| 10.0.0.1/30 \|\| 10.0.0.2/30
Line 53:		Line 53:
	version = "l2tpv3"		version = "l2tpv3"
	encap = "ip"		encap = "ip"
	local = "157.90.26.4:0"		local = "157.9.2.4:0"
	peer = "78.~~157~~.42.~~222~~:0"		peer = "85.57.4.221:0"
	tid = 100		tid = 100
	ptid = 200		ptid = 200
Line 112:		Line 112:

	<syntaxhighlight lang="text">		<syntaxhighlight lang="text">
	/interface l2tp-ether add name=l2tpv3 connect-to=157.90.26.4 local-address=78.~~157~~.42.~~222~~ local-tunnel-id=200 remote-tunnel-id=100 local-session-id=2000 remote-session-id=1000 l2tp-proto-version=l2tpv3-ip unmanaged-mode=yes disabled=no		/interface l2tp-ether add name=l2tpv3 connect-to=157.9.2.4 local-address=85.57.4.221 local-tunnel-id=200 remote-tunnel-id=100 local-session-id=2000 remote-session-id=1000 l2tp-proto-version=l2tpv3-ip unmanaged-mode=yes disabled=no

	/ip address add address=10.0.0.2/30 interface=l2tpv3		/ip address add address=10.0.0.2/30 interface=l2tpv3

Karavi: Created page with "== L2TPv3 Tunnel: Linux to MikroTik == === Overview === This guide explains how to set up a static L2TPv3 site-to-site tunnel between a Linux server and a MikroTik router using `ql2tpd` from the `go-l2tp` package. {| class="wikitable" ! !! Server !! Client |- | '''Device''' || Ubuntu 24.04 || MikroTik RouterOS 7.20+ |- | '''Public IP''' || 157.90.26.4 || 78.157.42.222 |- | '''Tunnel IP''' || 10.0.0.1/30 || 10.0.0.2/30 |- | '''Tunnel ID''' || 100..."

2026-06-21T19:38:06Z

Created page with "== L2TPv3 Tunnel: Linux to MikroTik == === Overview === This guide explains how to set up a static L2TPv3 site-to-site tunnel between a Linux server and a MikroTik router using <code>ql2tpd</code> from the <code>go-l2tp</code> package. {| class="wikitable" ! !! Server !! Client |- | '''Device''' || Ubuntu 24.04 || MikroTik RouterOS 7.20+ |- | '''Public IP''' || 157.90.26.4 || 78.157.42.222 |- | '''Tunnel IP''' || 10.0.0.1/30 || 10.0.0.2/30 |- | '''Tunnel ID''' || 100..."

New page

== L2TPv3 Tunnel: Linux to MikroTik ==

=== Overview ===

This guide explains how to set up a static L2TPv3 site-to-site tunnel between a Linux server and a MikroTik router using <code>ql2tpd</code> from the <code>go-l2tp</code> package.

{| class="wikitable"
! !! Server !! Client
|-
| '''Device''' || Ubuntu 24.04 || MikroTik RouterOS 7.20+
|-
| '''Public IP''' || 157.90.26.4 || 78.157.42.222
|-
| '''Tunnel IP''' || 10.0.0.1/30 || 10.0.0.2/30
|-
| '''Tunnel ID''' || 100 || 200
|-
| '''Session ID''' || 1000 || 2000
|}

---

=== Prerequisites ===

* Ubuntu 24.04 (kernel 6.8+)
* MikroTik RouterOS 7.20 or later
* Root access on both devices
* IP protocol 115 allowed in firewall on both sides

---

=== Linux Server Setup ===

==== 1. Install packages ====

<syntaxhighlight lang="bash">
apt install -y linux-modules-extra-$(uname -r) go-l2tp
</syntaxhighlight>

==== 2. Load kernel modules ====

<syntaxhighlight lang="bash">
modprobe l2tp_eth l2tp_ip l2tp_netlink
echo -e "l2tp_eth\nl2tp_ip\nl2tp_netlink" > /etc/modules-load.d/l2tp.conf
</syntaxhighlight>

==== 3. Create ql2tpd configuration ====

<syntaxhighlight lang="bash">
mkdir -p /etc/ql2tpd
cat > /etc/ql2tpd/ql2tpd.toml << 'EOF'
[tunnel.t1]
version = "l2tpv3"
encap = "ip"
local = "157.90.26.4:0"
peer = "78.157.42.222:0"
tid = 100
ptid = 200

[tunnel.t1.session.s1]
pseudowire = "eth"
sid = 1000
psid = 2000
interface_name = "l2tpeth0"
EOF
</syntaxhighlight>

==== 4. Create systemd service ====

<syntaxhighlight lang="bash">
cat > /etc/systemd/system/ql2tpd.service << 'EOF'
[Unit]
Description=L2TPv3 Static Tunnel
After=network.target

[Service]
ExecStart=/usr/sbin/ql2tpd -config /etc/ql2tpd/ql2tpd.toml
Restart=always

[Install]
WantedBy=multi-user.target
EOF

systemctl enable --now ql2tpd
</syntaxhighlight>

==== 5. Assign tunnel IP ====

<syntaxhighlight lang="bash">
sleep 2
ip addr add 10.0.0.1/30 dev l2tpeth0
ip link set l2tpeth0 up
</syntaxhighlight>

==== 6. Persist IP after reboot ====

<syntaxhighlight lang="bash">
cat > /etc/networkd-dispatcher/routable.d/l2tp-ip.sh << 'EOF'
#!/bin/bash
sleep 3
ip addr add 10.0.0.1/30 dev l2tpeth0 2>/dev/null
ip link set l2tpeth0 up 2>/dev/null
EOF
chmod +x /etc/networkd-dispatcher/routable.d/l2tp-ip.sh
</syntaxhighlight>

---

=== MikroTik Client Setup ===

Run the following commands in the MikroTik terminal:

<syntaxhighlight lang="text">
/interface l2tp-ether add name=l2tpv3 connect-to=157.90.26.4 local-address=78.157.42.222 local-tunnel-id=200 remote-tunnel-id=100 local-session-id=2000 remote-session-id=1000 l2tp-proto-version=l2tpv3-ip unmanaged-mode=yes disabled=no

/ip address add address=10.0.0.2/30 interface=l2tpv3
</syntaxhighlight>

{{Note|<code>unmanaged-mode=yes</code> is required. Without it, MikroTik attempts to run the L2TPv3 control protocol, which <code>ql2tpd</code> does not support since it operates as a static (data-plane only) daemon.}}

---

=== Verification ===

'''From Linux server:'''

<syntaxhighlight lang="bash">
ping 10.0.0.2 -c 4
</syntaxhighlight>

'''From MikroTik:'''

<syntaxhighlight lang="text">
/ping 10.0.0.1 count=4
</syntaxhighlight>

---

=== Cleanup ===

'''Linux server:'''

<syntaxhighlight lang="bash">
systemctl stop ql2tpd
systemctl disable ql2tpd
rm /etc/systemd/system/ql2tpd.service
rm -rf /etc/ql2tpd
rm -f /etc/networkd-dispatcher/routable.d/l2tp-ip.sh
rm -f /etc/modules-load.d/l2tp.conf
systemctl daemon-reload
ip link del l2tpeth0 2>/dev/null
modprobe -r l2tp_eth l2tp_ip l2tp_netlink 2>/dev/null
apt remove -y go-l2tp
</syntaxhighlight>

'''MikroTik:'''

<syntaxhighlight lang="text">
/ip address remove [find interface=l2tpv3]
/interface l2tp-ether remove l2tpv3
</syntaxhighlight>

---

=== Troubleshooting ===

{| class="wikitable"
! Symptom !! Cause !! Fix
|-
| <code>Module l2tp_eth not found</code> || Missing extra modules || <code>apt install linux-modules-extra-$(uname -r)</code>
|-
| Interface not created || <code>ql2tpd</code> not running in background || Run with <code>&</code> or use systemd service
|-
| Link stays DOWN || MikroTik sending control messages || Add <code>unmanaged-mode=yes</code>
|-
| No packets arriving || Firewall blocking proto 115 || Allow IP protocol 115 on both sides
|-
| IP lost after reboot || No persistence script || Add networkd-dispatcher script (step 6)
|}

---

=== Notes ===

* <code>ql2tpd</code> is a static (quiescent) L2TPv3 daemon — it does '''not''' run the L2TPv3 control protocol. Both peers must have matching tunnel and session IDs configured manually.
* MikroTik <code>l2tp-ether</code> with <code>unmanaged-mode=yes</code> bypasses the control protocol and operates as a pure static data plane, making it compatible with <code>ql2tpd</code>.
* The tunnel carries raw Ethernet frames (pseudowire type: <code>eth</code>), making it suitable for Layer 2 bridging between sites.
* No encryption is applied by default. For production use, consider wrapping the tunnel with IPsec.

---

=== References ===

* [https://github.com/katalix/go-l2tp go-l2tp GitHub]
* [https://manpages.ubuntu.com/manpages/oracular/man5/ql2tpd.toml.5.html ql2tpd.toml man page]
* [https://www.rfc-editor.org/rfc/rfc3931 RFC 3931 — L2TPv3]
* [https://www.rfc-editor.org/rfc/rfc4719 RFC 4719 — L2TPv3 Ethernet Pseudowire]

Mikrotik Ubuntu L2TPv3 - Revision history

Karavi at 19:42, 21 June 2026