Problema con account VoIP

[wicom]

Ciao Ragazzi
Ho un problema su una centrale VoIP 3cx, vi spiego brevemente il problema:

Il server 3cx è posizionato da un mio cliente che ha una adsl fornita da un piccolo WISP, che gestisco io tra l'altro, inizialmente a monte avevo un router cisco 877 che nattava tutto su un IP pubblico e tutti erano felici e contenti sia per l'adls sia per gli account voip che ci sono sulla rete.
Successivamente ho fatto un upgrade di linea, ho messo un cisco 1841 con 2 linee 4 MB affasciate ed ho migrato tutte le connessioni dalla vecchia linea alla nuova, su queste due linee mi sono fatto assegnare un pool di indirizzi IP Pubblici che man mano vado assegnando ai miei clienti.
Nel trapasso tutto bene gli ip pubblici arrivano sul mio firewall dove viene fatto un NAT 1:1 cossì che li'IP pubblico passa a privato e arriva direttamente sulla CPE del mio cliente, anche questa cosa funziona bene.
L'unica cosa che non mi funzone e che mi sta facendo impazziere è che non riesco a far associare l'account voip sulla centrale del mio cliente.
Vi scrivo il log della centrale e come se lui inviasse la richiesta di autenticazione al server sip del provider voip ma questa richiesta viene droppata da qualche parte.

Kissa dove??:

23:10:36.515 [CM506004]: STUN request to STUN server 75.101.138.128:3478 has timed out; used Transport: 192.168.1.170:5060
23:10:36.406 [CM506001]: STUN request to resolve SIP external IPort mapping is sent to STUN server 75.101.138.128:3478 over Transport 192.168.1.170:5060
23:10:26.062 [CM504003]: Sent registration request for 10000@Exsorsa
23:08:56.484 [CM506004]: STUN request to STUN server 75.101.138.128:3478 has timed out; used Transport: 192.168.1.170:5060
23:08:56.375 [CM506001]: STUN request to resolve SIP external IPort mapping is sent to STUN server 75.101.138.128:3478 over Transport 192.168.1.170:5060
23:07:16.375 [CM506004]: STUN request to STUN server 75.101.138.128:3478 has timed out; used Transport: 192.168.1.170:5060
23:07:16.265 [CM506001]: STUN request to resolve SIP external IPort mapping is sent to STUN server 75.101.138.128:3478 over Transport 192.168.1.170:5060
23:05:36.296 [CM506004]: STUN request to STUN server 75.101.138.128:3478 has timed out; used Transport: 192.168.1.170:5060
23:05:36.187 [CM506001]: STUN request to resolve SIP external IPort mapping is sent to STUN server 75.101.138.128:3478 over Transport 192.168.1.170:5060
23:03:56.218 [CM506004]: STUN request to STUN server 75.101.138.128:3478 has timed out; used Transport: 192.168.1.170:5060
23:03:56.109 [CM506001]: STUN request to resolve SIP external IPort mapping is sent to STUN server 75.101.138.128:3478 over Transport 192.168.1.170:5060
23:02:16.140 [CM506004]: STUN request to STUN server 75.101.138.128:3478 has timed out; used Transport: 192.168.1.170:5060
23:02:16.031 [CM506001]: STUN request to resolve SIP external IPort mapping is sent to STUN server 75.101.138.128:3478 over Transport 192.168.1.170:5060
23:00:36.062 [CM506004]: STUN request to STUN server 75.101.138.128:3478 has timed out; used Transport: 192.168.1.170:5060
23:00:35.953 [CM506001]: STUN request to resolve SIP external IPort mapping is sent to STUN server 75.101.138.128:3478 over Transport 192.168.1.170:5060
23:00:26.031 [CM504007]: Next attempt to register 10000@Exsorsa is scheduled in 10 minutes
23:00:26.031 [CM504005]: Registration failed for: 10000@Exsorsa; Cause: 408 Request Timeout; internal
22:58:56.015 [CM506004]: STUN request to STUN server 75.101.138.128:3478 has timed out; used Transport: 192.168.1.170:5060
22:58:55.906 [CM506001]: STUN request to resolve SIP external IPort mapping is sent to STUN server 75.101.138.128:3478 over Transport 192.168.1.170:5060
22:57:49.375 [CM504003]: Sent registration request for 10000@Exsorsa
22:57:15.906 [CM506004]: STUN request to STUN server 75.101.138.128:3478 has timed out; used Transport: 192.168.1.170:5060
22:57:15.796 [CM506001]: STUN request to resolve SIP external IPort mapping is sent to STUN server 75.101.138.128:3478 over Transport 192.168.1.170:5060
22:55:35.828 [CM506004]: STUN request to STUN server 75.101.138.128:3478 has timed out; used Transport: 192.168.1.170:5060
22:55:35.718 [CM506001]: STUN request to resolve SIP external IPort mapping is sent to STUN server 75.101.138.128:3478 over Transport 192.168.1.170:5060
22:53:55.781 [CM506004]: STUN request to STUN server 75.101.138.128:3478 has timed out; used Transport: 192.168.1.170:5060
22:53:55.671 [CM506001]: STUN request to resolve SIP external IPort mapping is sent to STUN server 75.101.138.128:3478 over Transport 192.168.1.170:5060
22:52:15.671 [CM506004]: STUN request to STUN server 75.101.138.128:3478 has timed out; used Transport: 192.168.1.170:5060
22:52:15.562 [CM506001]: STUN request to resolve SIP external IPort mapping is sent to STUN server 75.101.138.128:3478 over Transport 192.168.1.170:5060
22:50:35.671 [CM506004]: STUN request to STUN server 75.101.138.128:3478 has timed out; used Transport: 192.168.1.170:5060
22:50:35.562 [CM506001]: STUN request to resolve SIP external IPort mapping is sent to STUN server 75.101.138.128:3478 over Transport 192.168.1.170:5060
22:48:55.656 [CM506004]: STUN request to STUN server 75.101.138.128:3478 has timed out; used Transport: 192.168.1.170:5060
22:48:55.546 [CM506001]: STUN request to resolve SIP external IPort mapping is sent to STUN server 75.101.138.128:3478 over Transport 192.168.1.170:5060
22:47:49.375 [CM504007]: Next attempt to register 10000@Exsorsa is scheduled in 10 minutes
22:47:49.375 [CM504005]: Registration failed for: 10000@Exsorsa; Cause: 408 Request Timeout; internal
22:47:15.546 [CM506004]: STUN request to STUN server 75.101.138.128:3478 has timed out; used Transport: 192.168.1.170:5060
22:47:15.437 [CM506001]: STUN request to resolve SIP external IPort mapping is sent to STUN server 75.101.138.128:3478 over Transport 192.168.1.170:5060

Secondo voi dove sta il problema???