UDP Packets over VodaCom GPRS network

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MainMeat

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Hi - I have a small problem that is described below and hope someone from VodaCom can help me, or perhaps someone had a similar experience:

I have Telemetry units that reports information to a central system available on the Internet. These reports are sent using UDP Packets over the GPRS network to a IP address / URL on the internet (the central system).

For each report received, a acknowledgment is sent back to the unit to indicate a successful receipt of the report sent by the Telemetry Unit.

I have conducted some tests using a Private APN on the VodaCom network that I had access too and all worked fine. I now also tried these same tests using the 'internetvpn' APN provided by VodaCom as it is the only APN I know that will assign a public IP address to the Telemetry unit when it connects on the GPRS network.

The problem I now have is that I am able to send data form the Telemetry Unit to the Central system, but the acknowledgment Packet sent from the central system back to the telemetry unit fails and does not reach the unit. Various tests later seems to indicate that all incoming packets to the Telemetry unit is blocked somewhere in the VodaCom Network by a firewall or router.

Does anybody now if this is indeed the case, and is there a work around to send UDP Packets from the Internet to a Unit connected on the VodaCOM GPRS network.

Just a note: I also tried to establish a standard TCP/IP Socket Connection from the central system to a PC connected via GPRS - again the connection failed in this direction and I was only able to establish a connection from the PC connection via GPRS to the central system on the internet. Clearly all firewalls and routers was taken care of as these tests are successful when conducted using only the internet.

Any information on this topic is greatly appreciated!
 
Okay - thanks. I will apply and hopefully this will solve my problem!

Thanks
 
MainMeat said:
Hi - I have a small problem that is described below and hope someone from VodaCom can help me, or perhaps someone had a similar experience:

I have Telemetry units that reports information to a central system available on the Internet. These reports are sent using UDP Packets over the GPRS network to a IP address / URL on the internet (the central system).

For each report received, a acknowledgment is sent back to the unit to indicate a successful receipt of the report sent by the Telemetry Unit.

I have conducted some tests using a Private APN on the VodaCom network that I had access too and all worked fine. I now also tried these same tests using the 'internetvpn' APN provided by VodaCom as it is the only APN I know that will assign a public IP address to the Telemetry unit when it connects on the GPRS network.

The problem I now have is that I am able to send data form the Telemetry Unit to the Central system, but the acknowledgment Packet sent from the central system back to the telemetry unit fails and does not reach the unit. Various tests later seems to indicate that all incoming packets to the Telemetry unit is blocked somewhere in the VodaCom Network by a firewall or router.

Does anybody now if this is indeed the case, and is there a work around to send UDP Packets from the Internet to a Unit connected on the VodaCOM GPRS network.

Just a note: I also tried to establish a standard TCP/IP Socket Connection from the central system to a PC connected via GPRS - again the connection failed in this direction and I was only able to establish a connection from the PC connection via GPRS to the central system on the internet. Clearly all firewalls and routers was taken care of as these tests are successful when conducted using only the internet.

Any information on this topic is greatly appreciated!
Click to expand...

Yes, it all makes sense. The internet and internetvpn apn's will block incoming connections as part of their rules. Even though you are making an outbound connection from the telemetry unit, it looks like the response coming back is seen as a new connection and is then blocked.

As morkhans suggested, switch the units to the unrestricted apn as these will allow unsolicited incoming connections.
 
vodacom3g said:
Yes, it all makes sense. The internet and internetvpn apn's will block incoming connections as part of their rules. Even though you are making an outbound connection from the telemetry unit, it looks like the response coming back is seen as a new connection and is then blocked.

As morkhans suggested, switch the units to the unrestricted apn as these will allow unsolicited incoming connections.
Click to expand...
The thing is that UDP is a connectionless exchange of IP packets, so there is no connection for Vodacom's stateful-firewall(s) to track, having said that, MainMeat should have been able to get a TCP connection going that would have worked with upper-level & non-standard ports on the internetvpn APN...
 
ic said:
The thing is that UDP is a connectionless exchange of IP packets, so there is no connection for Vodacom's stateful-firewall(s) to track, having said that, MainMeat should have been able to get a TCP connection going that would have worked with upper-level & non-standard ports on the internetvpn APN...
Click to expand...

Not in the incoming direction. Still need the unrestricted apn for that.
 
No TCP Connection was possible and it seems V3G is right in that no incoming packets are allowed. I applied for the Unrestricted APN yesterday morning at 11:00 - still waiting for VodaCom to come back to me and will call the data help desk if I have not heard anything from them by lunch time.

Thanks for the help and info thus far - I will keep the thread updated once I have had some success...

(V3G - just a note. When I initially called the Data Help Desk I was informed that it was a configuration issue in my application, although it does now seem that it is how Vodacom configured the APNs. Perhaps a short memo to the data help desk guys describing the symptom and solution to this will be a good thing for future reference.)

Thanks
 
MainMeat said:
No TCP Connection was possible and it seems V3G is right in that no incoming packets are allowed. I applied for the Unrestricted APN yesterday morning at 11:00 - still waiting for VodaCom to come back to me and will call the data help desk if I have not heard anything from them by lunch time.
Click to expand...

It took about a day and a bit for my application to be processed. I got a SMS to say it was activated.
 
Thanks, Got it activated and packets are now received in both directions.
 
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