Network issue

Hi every one

I have installed Asterisk 1.8.7 in Ubuntu oneiric. And I have a LAN with Asterisk server and two phones:
A hard phone SPA 942 (extension 2000) and a 3CXPhone (extension 2004) both are in the same LAN and have the IP and respectively. With a subnet
The two phones above work perfectly I can make a call from and to each of witch and I have two way audio. It’s Ok

And I have another 3CXPhone in an external LAN (extension 2001) and an IP
This phone can ring the two local phones But with no sound (no audio at all).
And no one of the local phones (2000-2004) can ring the external phone (2001)

The external phone (2001) can register to my asterisk server but it’s status is UNREACHABLE.
I can recognize that all the phones are registered with there local IP address.
when I execute the command :
sip show peers I get this

Name/username Host Dyn Forcerport ACL Port Status
2000/hard phone D 5060 OK
2001/soft phone D 3697 OK
2004/Az soft Phone D 3215 UNREACHABLE

The sip.conf file

localnet =

all the peers have:
type = friend
host = dynamic

and my iptables is as follow:

iptables --flush           		
iptables --table nat --flush
iptables --delete-chain     
iptables --table nat --delete-chain
iptables --table nat --append POSTROUTING --out-interface ppp0 -j MASQUERADE
iptables --append FORWARD --in-interface eth0 -j ACCEPT

echo 1 > /proc/sys/net/ipv4/ip_forward

I’m struggling here simply couldn’t make it work. And I believe that it is a network issu.
Any help will be appreciated.
Best regards

Did you change anything lately to the configuration of the phone or the sip.conf?

i would say: reset the phone and configure it again…

On the network it looks like your localnet netmask ending in .225 indicates that the external phone is inside the local subnet.

The mask should be not

That would allow one way traffic from the outside in, but traffic would not exit the * on the outside interface.

Sharp eye! Nice!

Thinks tom for your replies. Yes sharp eye but this is not the cause, in fact the brd is in my file
the problem was the speed of the NIC of the server in one hand and in the other hand was the configuration of both the hardphone and the soft phone.
And thinks agin for your replies.
Best regards.