Karavi at 19:48, 21 June 2026

2026-06-21T19:48:47Z

Karavi: Created page with "== L2TPv3 Tunnel: One Linux Server to Multiple MikroTik Routers == === Overview === This guide explains how to connect one Linux server to six MikroTik routers using static L2TPv3 tunnels via `ql2tpd`. {| class="wikitable" ! # !! MikroTik IP !! Server Tunnel IP !! Client Tunnel IP !! tid !! ptid !! sid !! psid |- | 0 (existing) || 78.157.42.222 || 10.0.0.1/30 || 10.0.0.2/30 || 100 || 200 || 1000 || 2000 |- | 1 || 85.57.4.221 || 10.0.1.1/30 || 10.0.1.2/30 ||..."

2026-06-21T19:44:32Z

Created page with "== L2TPv3 Tunnel: One Linux Server to Multiple MikroTik Routers == === Overview === This guide explains how to connect one Linux server to six MikroTik routers using static L2TPv3 tunnels via <code>ql2tpd</code>. {| class="wikitable" ! # !! MikroTik IP !! Server Tunnel IP !! Client Tunnel IP !! tid !! ptid !! sid !! psid |- | 0 (existing) || 78.157.42.222 || 10.0.0.1/30 || 10.0.0.2/30 || 100 || 200 || 1000 || 2000 |- | 1 || 85.57.4.221 || 10.0.1.1/30 || 10.0.1.2/30 ||..."

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== L2TPv3 Tunnel: One Linux Server to Multiple MikroTik Routers ==

=== Overview ===

This guide explains how to connect one Linux server to six MikroTik routers using static L2TPv3 tunnels via <code>ql2tpd</code>.

{| class="wikitable"
! # !! MikroTik IP !! Server Tunnel IP !! Client Tunnel IP !! tid !! ptid !! sid !! psid
|-
| 0 (existing) || 78.157.42.222 || 10.0.0.1/30 || 10.0.0.2/30 || 100 || 200 || 1000 || 2000
|-
| 1 || 85.57.4.221 || 10.0.1.1/30 || 10.0.1.2/30 || 101 || 201 || 1001 || 2001
|-
| 2 || 85.57.4.222 || 10.0.2.1/30 || 10.0.2.2/30 || 102 || 202 || 1002 || 2002
|-
| 3 || 85.57.4.223 || 10.0.3.1/30 || 10.0.3.2/30 || 103 || 203 || 1003 || 2003
|-
| 4 || 85.57.4.224 || 10.0.4.1/30 || 10.0.4.2/30 || 104 || 204 || 1004 || 2004
|-
| 5 || 85.57.4.225 || 10.0.5.1/30 || 10.0.5.2/30 || 105 || 205 || 1005 || 2005
|}

---

=== Linux Server Setup (<code>157.90.26.4</code>) ===

==== 1. Update ql2tpd configuration ====

<syntaxhighlight lang="bash">
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"

[tunnel.t2]
version = "l2tpv3"
encap = "ip"
local = "157.90.26.4:0"
peer = "85.57.4.221:0"
tid = 101
ptid = 201
[tunnel.t2.session.s1]
pseudowire = "eth"
sid = 1001
psid = 2001
interface_name = "l2tpeth1"

[tunnel.t3]
version = "l2tpv3"
encap = "ip"
local = "157.90.26.4:0"
peer = "85.57.4.222:0"
tid = 102
ptid = 202
[tunnel.t3.session.s1]
pseudowire = "eth"
sid = 1002
psid = 2002
interface_name = "l2tpeth2"

[tunnel.t4]
version = "l2tpv3"
encap = "ip"
local = "157.90.26.4:0"
peer = "85.57.4.223:0"
tid = 103
ptid = 203
[tunnel.t4.session.s1]
pseudowire = "eth"
sid = 1003
psid = 2003
interface_name = "l2tpeth3"

[tunnel.t5]
version = "l2tpv3"
encap = "ip"
local = "157.90.26.4:0"
peer = "85.57.4.224:0"
tid = 104
ptid = 204
[tunnel.t5.session.s1]
pseudowire = "eth"
sid = 1004
psid = 2004
interface_name = "l2tpeth4"

[tunnel.t6]
version = "l2tpv3"
encap = "ip"
local = "157.90.26.4:0"
peer = "85.57.4.225:0"
tid = 105
ptid = 205
[tunnel.t6.session.s1]
pseudowire = "eth"
sid = 1005
psid = 2005
interface_name = "l2tpeth5"
EOF
</syntaxhighlight>

==== 2. Restart service ====

<syntaxhighlight lang="bash">
systemctl restart ql2tpd
sleep 2
</syntaxhighlight>

==== 3. Assign tunnel IPs ====

<syntaxhighlight lang="bash">
ip addr add 10.0.1.1/30 dev l2tpeth1 && ip link set l2tpeth1 up
ip addr add 10.0.2.1/30 dev l2tpeth2 && ip link set l2tpeth2 up
ip addr add 10.0.3.1/30 dev l2tpeth3 && ip link set l2tpeth3 up
ip addr add 10.0.4.1/30 dev l2tpeth4 && ip link set l2tpeth4 up
ip addr add 10.0.5.1/30 dev l2tpeth5 && ip link set l2tpeth5 up
</syntaxhighlight>

==== 4. Persist IPs 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
ip addr add 10.0.1.1/30 dev l2tpeth1 2>/dev/null && ip link set l2tpeth1 up 2>/dev/null
ip addr add 10.0.2.1/30 dev l2tpeth2 2>/dev/null && ip link set l2tpeth2 up 2>/dev/null
ip addr add 10.0.3.1/30 dev l2tpeth3 2>/dev/null && ip link set l2tpeth3 up 2>/dev/null
ip addr add 10.0.4.1/30 dev l2tpeth4 2>/dev/null && ip link set l2tpeth4 up 2>/dev/null
ip addr add 10.0.5.1/30 dev l2tpeth5 2>/dev/null && ip link set l2tpeth5 up 2>/dev/null
EOF
chmod +x /etc/networkd-dispatcher/routable.d/l2tp-ip.sh
</syntaxhighlight>

---

=== MikroTik 1 — <code>85.57.4.221</code> ===

<syntaxhighlight lang="text">
/interface l2tp-ether add name=l2tpv3 connect-to=157.90.26.4 local-address=85.57.4.221 local-tunnel-id=201 remote-tunnel-id=101 local-session-id=2001 remote-session-id=1001 l2tp-proto-version=l2tpv3-ip unmanaged-mode=yes disabled=no
/ip address add address=10.0.1.2/30 interface=l2tpv3
</syntaxhighlight>

---

=== MikroTik 2 — <code>85.57.4.222</code> ===

<syntaxhighlight lang="text">
/interface l2tp-ether add name=l2tpv3 connect-to=157.90.26.4 local-address=85.57.4.222 local-tunnel-id=202 remote-tunnel-id=102 local-session-id=2002 remote-session-id=1002 l2tp-proto-version=l2tpv3-ip unmanaged-mode=yes disabled=no
/ip address add address=10.0.2.2/30 interface=l2tpv3
</syntaxhighlight>

---

=== MikroTik 3 — <code>85.57.4.223</code> ===

<syntaxhighlight lang="text">
/interface l2tp-ether add name=l2tpv3 connect-to=157.90.26.4 local-address=85.57.4.223 local-tunnel-id=203 remote-tunnel-id=103 local-session-id=2003 remote-session-id=1003 l2tp-proto-version=l2tpv3-ip unmanaged-mode=yes disabled=no
/ip address add address=10.0.3.2/30 interface=l2tpv3
</syntaxhighlight>

---

=== MikroTik 4 — <code>85.57.4.224</code> ===

<syntaxhighlight lang="text">
/interface l2tp-ether add name=l2tpv3 connect-to=157.90.26.4 local-address=85.57.4.224 local-tunnel-id=204 remote-tunnel-id=104 local-session-id=2004 remote-session-id=1004 l2tp-proto-version=l2tpv3-ip unmanaged-mode=yes disabled=no
/ip address add address=10.0.4.2/30 interface=l2tpv3
</syntaxhighlight>

---

=== MikroTik 5 — <code>85.57.4.225</code> ===

<syntaxhighlight lang="text">
/interface l2tp-ether add name=l2tpv3 connect-to=157.90.26.4 local-address=85.57.4.225 local-tunnel-id=205 remote-tunnel-id=105 local-session-id=2005 remote-session-id=1005 l2tp-proto-version=l2tpv3-ip unmanaged-mode=yes disabled=no
/ip address add address=10.0.5.2/30 interface=l2tpv3
</syntaxhighlight>

---

=== Verification ===

'''From Linux server:'''

<syntaxhighlight lang="bash">
ping 10.0.1.2 -c 2
ping 10.0.2.2 -c 2
ping 10.0.3.2 -c 2
ping 10.0.4.2 -c 2
ping 10.0.5.2 -c 2
</syntaxhighlight>

'''From each MikroTik:'''

<syntaxhighlight lang="text">
/ping 10.0.X.1 count=4
</syntaxhighlight>

---

=== Troubleshooting ===

{| class="wikitable"
! Symptom !! Cause !! Fix
|-
| Interface not created || <code>ql2tpd</code> not restarted || <code>systemctl restart ql2tpd</code>
|-
| Link stays DOWN || MikroTik sending control messages || Verify <code>unmanaged-mode=yes</code>
|-
| No packets arriving || Firewall blocking proto 115 || Allow IP protocol 115 on both sides
|-
| IP lost after reboot || persistence script not updated || Re-run step 4
|-
| Wrong tunnel match || Duplicate tid/ptid/sid/psid || Verify IDs are unique per tunnel
|}

---

=== Notes ===

* Each tunnel must have unique <code>tid</code>, <code>ptid</code>, <code>sid</code>, and <code>psid</code> values.
* Each MikroTik's <code>local-tunnel-id</code> must match the server's <code>ptid</code> for that tunnel, and vice versa.
* All tunnels share the same Linux server public IP (<code>157.90.26.4</code>) — this is supported since each tunnel is differentiated by its tunnel ID.
* No encryption is applied by default. For production use, consider wrapping tunnels 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 one server six mikrotik - Revision history

Karavi at 19:48, 21 June 2026