• V20: 3CX Re-engineered. Get V20 for increased security, better call management, a new admin console and Windows softphone. Learn More.

SIP traffic is not allowed

Status
Not open for further replies.

Moawia Noor

Free User
Joined
Mar 12, 2017
Messages
29
Reaction score
0
Hi every one,

ISPs are blocking SIP traffic, as a result, we can't use 3cx remote apps, and it's ridiculous to ask customers to use VPN app whenever they are willing to connect remotely.

We tried to use different Ports instead of 5060 and 5090 but still no luck.

did anyone come across a similar situation? If not, Is there any possible workaround?

Any response is so appreciated.
 
Our 3CX Phones would use from external a 3CX proprietary protocol (3CX tunnel) which an ISP would not detect as SIP. But may they even do not allow non std. ports to be used such as 5090 and restrict your to 80 443 etc...

For IP Phones in a remote location you also could use the 3CX Tunnel while adding a 3CX SBC into your network.
 
  • Like
Reactions: Moawia Noor
If the ISP blocks a range of ports (all 50XX?), and you are unable to find something outside that blocked range, then VPN may be the only solution.
This would seem to be a common issue in a number of countries, where the government keeps a tight grip on telecommunications. Other than using VPN, i haven't heard of a magic bullet.
 
  • Like
Reactions: Moawia Noor
Our 3CX Phones would use from external a 3CX proprietary protocol (3CX tunnel) which an ISP would not detect as SIP. But may they even do not allow non std. ports to be used such as 5090 and restrict your to 80 443 etc...

For IP Phones in a remote location you also could use the 3CX Tunnel while adding a 3CX SBC into your network.

We've tried using different ports, even for the tunnel, I don't know how they are still able to detect the traffic as VOIP and block it?
 
If the ISP blocks a range of ports (all 50XX?), and you are unable to find something outside that blocked range, then VPN may be the only solution.
This would seem to be a common issue in a number of countries, where the government keeps a tight grip on telecommunications. Other than using VPN, i haven't heard of a magic bullet.


It's common with a alot of countries, cause even when using a VPN not all the host countries can allow the traffic...

We aren't looking for a magical move, it's a sience and there is always some workarounds If someone could explain the process ISP uses to filter VOIP traffic.

And I don't think they are very smart because they are failing to block Facebook messenger calls!
 
If someone could explain the process ISP uses to filter VOIP traffic.

That's the million dollar question. It is probably going to be different for each ISP unless there are specifications provided, by a government agency, that they must adhere to,
 
  • Like
Reactions: Moawia Noor
The 3CX mobile apps,even when using the Tunnel, the traffic is not 100% encrypted. The best way to describe it simply is that the mobile Clients "encapsulate" SIP and Audio/RTP into 1 stream and send/receive it over a single port.

I say this because the provide may still be detecting it this way, because in clear text you could see some SIP messages in the stream.

The SBC, which also uses the Tunnel however, you can encrypt the stream, so then it is not visible at all in clear text.

Encryption of the Tunnel on the 3CX Clients is not yet possible as it does require additional computing power (and you are running on battery), whereas the SBC is a stand-alone device. Let's see what happens in the future though...

Another way providers could detect SIP traffic is by "guessing". When they see a behavior that resembles Audio RTP exchange (small packets, same size, every 20-30ms), they start blocking it. I have seen the behavior in some of these countries where call starts normally, but after 20 seconds audio stops because it is being blocked.
 
  • Like
Reactions: Moawia Noor
Status
Not open for further replies.

Getting Started - Admin

Latest Posts

Forum statistics

Threads
141,618
Messages
748,853
Members
144,730
Latest member
Ilyass.b
Get 3CX - Absolutely Free!

Link up your team and customers Phone System Live Chat Video Conferencing

Hosted or Self-managed. Up to 10 users free forever. No credit card. Try risk free.

3CX
A 3CX Account with that email already exists. You will be redirected to the Customer Portal to sign in or reset your password if you've forgotten it.