Mikrotik to Ethernet 3G router

[Drunkard #1]

Hi all. I'm looking for help again. Sorry in advance, for not having a clue how to use my kit.

I normally use a modem in full bridge mode connected to Eth2, for internet, and the rest of the network connected to Eth1.

Now the ADSL failed, so I've just bought a 3G router with ethernet ports.

How do I configure the routerboard (Mikrotik RB433AH) to use the 3G router?

I've plugged the router directly into the network for now, but that's really not ideal: I have no clue whether it's got a firewall, and the DHCP server is on the routerboard (and if I change any IPs, everything has to be updated manually.), and without serious throttling the office wenches will use all 60 gigs in one day downloading pictures of cats, so I really need to just hook up the 3G router to the routerboard.

Anyone know how?

Thanks.

 

[Tim the Techxpert]

Hi There Drunkard,
You plug Ethernet WAN port of the router into one of the ports on 3G router and just make Gateway to be the ip address of 3G router.

Should work with no changes to your DHCP

Regards

Tim

 

[Drunkard #1]

Hi There Drunkard,
You plug Ethernet WAN port of the router into one of the ports on 3G router and just make Gateway to be the ip address of 3G router.

Should work with no changes to your DHCP

Regards

Tim

I've got it working, but not properly. The 3G router is plugged into the network hub (Eth2) with it's DHCP server turned off, and I've set up a route on the routerboard to use the 3G for all internet traffic. This works fine as long as each PC's gateway is the Mikrotik. If someone was to manually change their gateway, they'd bypass the Mikrotik's firewall and shaping.

What I wanted to do, that I can't get working is to plug the 3G router into Eth3.

Anyway, I'm not going to waste more time on this. Telkom said that my ADSL will be fixed within 48 hours.

 

[Matthysdt]

Hi Drunkard #1

You don't want to plug the 3G device in directly on the LAN, rather plug in into an open port on the Mikrotik, say ether3.

Then add a new default route as follows:
ip route add dst-address=0.0.0.0/0 gateway=ether3 distance=2

Make sure that the distance is more than the distance for the default route used by the ADSL (PPPoE).
This solution will work as an auto-failover and 3G will only be available when ADSL is down.

 

[Drunkard #1]

I tried that and it didn't work.

My ADSL is working again (after being down for A WEEK!!!! ), so maybe I'll try again, but it's not urgent.

 

[wetkit]

Have a look under IP, Firewall and NAT.
You should have a masquerade rule there for your ADSL PPPoE connection.
Now just create another seperate one for your 3G.

 

[Roman4604]

Then add a new default route as follows:
ip route add dst-address=0.0.0.0/0 gateway=ether3 distance=2

You cant just set a route to an Ethernet interface, that's ambiguous. Ethernet is a logical bus with many possible destinations. You need to also set a dst-address= to the LAN IP of the 3G router.

Naturally you cant have duplicate IP networks, so ether3 must be configured with a different IP net from your LAN ether2. The 3G router must also configured on this alternate IP net, with the /ip route dst-address= pointing to it. Furthermore the 3G router needs a static route back to you LAN IP net with the destination pointing to the RB's ether3 address.

Have a look under IP, Firewall and NAT.
You should have a masquerade rule there for your ADSL PPPoE connection.
Now just create another seperate one for your 3G.

Not the best way of doing it. The 3G modem will already NAT to the cellular network addressing, so traffic between ether1 & ether3 should just route through without NAT. This however relies on you being able to put in the static route back to the RB on the 3G router.