Hi there,
I have the following setup: RB951Ui-2nD in a standard config + LTE modem Huawei E3372. This is so called HiLink version which means it has it's own router with NAT inside with no ways to configure DMZ or whatever. RB gets a private address say 192.168.8.2 and makes a NAT for WiFi & Eth with 192.168.88.0/24.
Due to double NAT there is no way to connect a VoIP adapter or even a SIP client on any android phone connected to the WiFi.
Tried the following:
- SIP helper (ALG) on / off in IP->Firewall. With OFF doesn't even register. With ON registers, but can't make a call or can't disconnect a call made (wtf!)
- STUN or "keepalive" method selected in the gateway. Doesn't register with STUN, with "keepalive" - as above, registers but can't talk
Now the idea is to either:
1. Make a RB only act as a bridge so only the LTE modem would do the DHCP, NAT etc. But this is an "ugly" solution and I'd rather avoid it. (Btw. tried switching to bridge but didn't work at all, not sure what I did wrong)
2. Exclude one Ethernet port from the predefined bridge (the one for VoIP gateway), and bridge it with LTE interface so it would talk to the modem directly and would get a separate IP address, say 192.168.8.3 (just next to RB's WAN) straight from the modem and all the routing would skip RB's NAT. Do you think it would work and could you give me a step-by-step setup guide?
... or any other idea?