Speedfusion won't work with 4g SIM cards



I have a few (5) max700 routers and have started looking at trying to bond cellular data for when we turn up to a venue with a poor upload capacity.

Bit of background on my setup, the first router max700_1 is on a 80mbit fibre line at work, its behind a firewall but ports have been opened and speedfusion configured.

At the minute in testing I can get a speedfusion link perfectly fine from a second location (home) when I connect the second max700_2 to a independent fibre line, it handshakes and all is well.

Now if I replace the fibre line with a 4g LTE device either using telfonika RUT950 routers, mobile phone tethering or via a usb 4g modem it won’t work, just stops at creating tunnels and goes back to starting again.

I am using multiple SIM cards from 3, EE, vodaphone and smarty (3) and they all cause the same error.

My Questions :slight_smile:

Is this most likely I guess because the phone networks are effectively providing a nat IP address and not public?

How’s anyone else using speedfusion in the UK with the big phone networks? I need bonding mainly for higher capacity and a bit of failover.

Cheers for any help you can give me.



Sorry forgot to add:

Max700_1 is accessible from a static public IP address.
Max700_2 uses ddns which updates with the cellular networks IP address fine.

Both routers are configured via the UI and not from incontrol.


So long as the mobile Max700_2 on cellular has a speedfusion profile configured to connect outbound to the public IP of the first max700_1 on fibre then there is no reason a speedfusion tunnel can’t be built.

All UK mobile networks use Carrier grade NAT by default so inbound connections to a MAX device on cellular only will always fail - unless you specifically request a dedicated public IP from your MNO which is a shockingly bad idea - so don’t do that.

The alternative is to host a FusionHub virtual appliance in the cloud to provide bonding to the MAX 700_2. I can setup a trial FH in a UK datacentre for you to smash some data through if you’d like to test that.


Hi Martin,

Thank you for the reply, I appreciate the offer of the fusion setup, I really do but I don’t want to make work for you especially if the 4g Sims should be working.

Would you mind having a look at the settings I’m using please. I’ll write them out as I’ve taken the kit back to work just now. I must be doing something wrong, its weird I can see a speedfusion link when it’s fibre line at each end. When I add a 4g wan to the max700_2 the fibre line maintains the tunnel link but the 4g never joins, just says no link in speedfusion status.

Max700_1 sits behind firewall. Static public IP > draytek router > Dmz ip > max700_1 - can log into max700_1 from public ip
Speedfusion setup is:
Vlan name:test
Remote ID:max700_2
Remote password:test1234
Remote IP address: (blank)

Max700_2 - dynamic assigned 4g sims only as wan, can’t log into router unless from Lan.
Speedfusion setup is:
Vlan name:test
Remote ID:max700_1
Remote password:test1234
Remote IP address: 81.127.(max700_1 IP)

I can get screenshots maybe tomorrow.

Thank you,


Screenshots would likely help - PM them to me privately if you want to leave IPs and stuff visible. Otherwise you could give me temp IC2 access and I could verify the config for you.

Is the MAX 700 set up as a Draytek ‘True DMZ IP’ or are you forwarding individual ports?

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Hi Martin,

Thanks for the offer of help, I’ll certainly get the details over to you if you dont mind but it won’t be for a fortnight.

I’ve had to send the current rack out as is for the next week or two, it has all the activated 4g routers buily into it. It’s expected back towards the end of May and I’m not back in the office until 25th May.
I’ll be able to leave it connected at work and give you whatever access is easiest for you.

I did try both port forwarding and as a true DMZ, it appears to handshake via fibre WANs, just the 4g side of things wasn’t happy which I hope is something I’m just doing wrong.


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