SIP and NAT

RouterOS General
1

Hi All,
I have some SIP-clients (AVM Fritzbox ATA) in a private subnet behind a MT server with a public IP and NAT:

/ip firewall nat add  chain=srcnat  src-address 10.0.0.0/24 action=masquerade disabled=no

The Problem is that I can receive calls and everything works correctly but when calls are attempted out, there is no ringtone and conversations.
If I replace the ROS server to a LinuxPC with

iptables -t nat -I POSTROUTING -s 10.0.0.0/24 -j MASQUERADE

everything works fine.
I have switched on and off sip helper without any effect.
I think I have to screw on connection tracking.
Any ideas?

2

Keep on using RouterOS! :wink:

3

Have you been able to fix this problem? I have a similar one. I have 5060 and 5061 open, I can send and receive calls, but, when I am initiating a call, I do not hear the RINGTONE in my ear, the called phone rings at the other end and if taken off hook (Answered), a conversation (two-way) works just fine.

I can receive calls just fine and my VOIP phone rings..

Any help will be appreciated.

BTW, if I plug the ATA into a dlink commodity router this problem goes away.

GAF