This article explains how to properly configure your Openwrt based router to work with Mikrotik antenna like this or this with LTE pass through feature enabled.
I had a typical setup for my home router. Home network + wan internet via 3g stick.
Later I've decided to replace 3g stick to LTE antenna to gain all benefits of LTE high speed and now my setup looks like this.
When I bought and configured Mikrotik antenna it turned out that it is a boarder device now, not router anymore.
So I have to configure all the stuff like firewall/port forwarding/traffic rules/security on the Mikrotik device.
That is annoying and not convenient.
I just want my Mikrotik antenna to act like my old 3g stick plugged into my router. Simple radio signal receiver not a separate network device that has a complex configuration.
Luckily, Mikrotik shipped new version of Router OS v6.41 with the feature calls LTE passthrough.
It means that Mikrotik device passes through WAN IP obtained from internet provided to Openwrt based router, and we do all configuration/firewalling/security on the router as we did before and don't need to deal with all the configuration burden in the Mikrotik Router OS anymore.
All instructions provided here was tested against Mikrotik antenna LHG LTE6 kit (Router OS 6.49) and router TP-Link Archer C7 v2 (openwrt 19.07).
For Router OS configuration I use Winbox tool.
- Network -> Switch
- Enable VLAN functionality
- Add 2 VLAN's as shown on the picture bellow
- VLAN 2 untagged (management VLAN)
- VLAN 3 tagged (internet VLAN)
- Click Save & Apply
- Network -> Interfaces -> Add new interface
- Name: whatever you want
- Protocol: Static address
- Interface: Switch VLAN: "eth0.2"
- Click "Create Interface"
- IPv4 address: IP from your Mikrotik network range (in my case 192.168.100.2, because Mikrotik itself has ip 192.168.100.1)
- IPv4 netmask: 255.255.255.0
- Click "Save"
- Click "Save & Apply"
- Network -> Interfaces -> Add new interface
- Name: whatever you want (in my case WAN)
- Protocol: DHCP client
- Interface: Switch VLAN: "eth0.3"
- Click "Create Interface"
- Check "Bring up on boot"
- REMEMBER MAC ADDRESS FROM THIS STEP
- Click "Save"
- Click "Save & Apply"
- Interfaces -> Interface (tab) -> select ether1 -> Click big plus -> VLAN
- Name: whatever you want
- VLAN ID: 2
- Interface: ether1
- Click OK
- Interfaces -> Interface (tab) -> select ether1 -> Click big plus -> VLAN
- Name: whatever you want
- VLAN ID: 3
- Interface: ether1
- Click OK
- Interfaces -> LTE (tab) -> select lte1 -> Click LTE APNs -> double-click default
- Passthrough interface: name from step 2 (in my case vlan-3-internet)
- Passthr. MAC address: mac address from step 3 on the openwrt side
- Click OK