I’ve done as much reading of these forums as I can on this topic, and I think I have things correctly configured, but I’m still getting a DHCP address allocated from the Mikrotik, not the ISP (ie I can see it in the DHCP leases of the Mikrotik).
So, firstly, my setup:
- Mikrotik EG12-EA based device (cAP LTE12 ax)
- Unifi gateway
The MT should be, as much as possible, just an LTE modem, I don’t need any other functionality from it. It’s configured as a router on a stick essentially, with management and wan clan’s, and connected to the wan2 port of my unifi, which all works fine, but there are two things which don’t work, ip-type=ipv4-ipv6 and passthrough (or I misunderstand what passthrough should do).
When I connect to my ISP via LTE this is the state:
> /ip/dhcp-server/pr
Flags: D - DYNAMIC
Columns: NAME, INTERFACE, ADDRESS-POOL, LEASE-TIME
# NAME INTERFACE ADDRESS-POOL LEASE-TIME
0 D default wan vlan static-only 1m
Note the “D” flag, indicating it is dynamically created, which means I can’t delete it.
> /ip/dhcp-server/lease/print
Flags: D - DYNAMIC
Columns: ADDRESS, MAC-ADDRESS, SERVER, STATUS, LAST-SEEN
# ADDRESS MAC-ADDRESS SERVER STATUS LAST-SEEN
0 D 10.208.232.9 1C:0B:8B:12:90:D1 default bound 5s
I can see it has an active lease to my unifi gateway… which to my mind defeats the purpose of passthrough? Shouldn’t the gateway get assigned an IP from my ISP? Note that the carrier definitely uses CGNAT, so I’m not expecting to see a public IP here, but seeing a different IP assigned to the (vlan) interface and the gateway along with an active DHCP lease on the MT device… seems wrong.
My partial config:
/interface lte
set [ find default-name=lte1 ] allow-roaming=no band="" mtu=1900
/interface lte apn
set [ find default=yes ] apn=yesinternet ip-type=ipv4 passthrough-interface="wan vlan" passthrough-mac=1C:0B:8B:12:90:D1 use-network-apn=no
/interface lte settings
set mode=mbim
The second issue, which isn’t really important, is that ip-type=ipv4-ipv6 doesn’t seem to exist for me. The carrier supports both (and I can individually select either ipv4 or ipv6).
What am I doing wrong?
EDIT: Forgot to say, I’ve tried this on a few different routers versions, currently running 7.20beta2, and latest modem firmware.
I’m beginning to think this is just how it works, MT get DHCP assigned addresses from ISP and uses a dynamic DHCP server to serve one of these to the downstream. So there is no NAT involved (well other than the CGNAT in this case), but I’m effectively grabbing 2 IPs from the ISP. Maybe this is fine, but it’s not clear from the doc if this is actually the case?