Hello,

I have a Draytek 2860 and a Huawei E3372h 4G dongle. Works fine on DHCP mode but does not allow SIP or any type of port forwarding.
Does anyone have any experience of a 4G dongle that will work with SIP and allow ports to be forwarded?

Thanks for any help.

I might have missed the point but the dongle itself shouldn't prevent either of those. Is it the ISP or that it's a NATTed IP address from the mobile ISP that is the problem ? This is a USB dongle? Using PPP or what ?

Yes it's an USB dongle and it's using DHCP mode - I don't believe it supports PPP mode - it's uses Hilink, where the dongle has it's own webui (192.168.8.1) and gives the Draytek WAN an IP (192.168.8.100) from what I can see there is no way to change any settings. The USB dongle acts likes it's own router/firewall it looks like.
ISP is a static public IP (m2m SIM) - no NAT.

Well, I think the problem, as you say, is that the dongle you have is acting as a router and NATTing stuff, blocking what you need... A traditional dongle wouldn';t do that but they're getting hard to get hold of, so the simplest (but most expensive!) solution is to get a Vigor2862Ln with the LTE built-in...

You should be able to set a DMZ to .100. That way you can access remotely, if using a SIM card that allows a Public IP, I.E. Three using the "3internet" APN.