Region : Argentina

Model : TL-ER6120

Hardware Version : V1

Firmware Version :

ISP :

I'm having troubles with the TL-ER6020.
My phones can not register behind this router.
i tested with the following:

Freeswitch server <--- Internet ---> Cable modem <--- TL-ER6020 ---> Linksys SPA941

Router is working fine except the phones won't register.
I checked the debug log of the freeswitch server and the phone sends a register request to the server but
somehow the reply from the server does not reach the phone.

I also tested the following :
Freeswitch server <--- TL-ER6020 ---> Linksys SPA941

same results :(

when i test this
Freeswitch server <--- {an old cheap router} ---> Linksys SPA941
It works just fine.

I tried the following:
Disable the the SIP ALG.
Then updated to the 130618 firmware.
Tried to turn of as much features off as posible.
Hooked the phone to the DMZ port and enabled DMZ (yeah getting desperate)
Tried all system moded (NAT, non-NAT, Classic)
Rebooted after every setting changes (router and phone)

Does anyone have any ideas :rolleyes:, otherwise this router is going back to the supplier because its useless for me if this is not working.