The Telstra Next G 3G internet service is fast, works well in a lot of areas around Australia and can be sorted out fairly cheaply these days.
One big downside to the service however is that by default you receive an IP address that is behind a firewall that performs NAT. Generally this isn’t an issue however for some more specific tasks it either makes life more difficult than necessary and makes some other things downright impossible.
One manifestation of this issue is the inability to connect to some corporate VPNs. The reason for this is that the Next G service gives you an IP address on the 10.0.0.0/8 subnet and a lot of corporate networks also use this range.
Fortunately a solution is at hand – telstra.extranet or GPTEXB3.
Unfortunately, you need to call Telstra to get this activated and a lot of the people you speak to won’t know about it and will transfer you to the wrong department.
If you call Telstra on 125111 (this is their Mobile Billing department) they are the people who can activate this, but they will transfer you to a number of other people first before you get a resolution.
What you need to do is explain to them that you’re using the telstra.internet APN and can’t connect to your VPN at work. You need a public IP address and this can be provided via the telstra.extranet APN. In order for you to be able to use the telstra.extranet APN, you need to have the option GPTEXB3 applied to your account.
Sounds easy? It only took me 35 minutes and being transferred around in circles, but was eventually able to speak to someone in billing. This person was going to transfer me somewhere else and I requested that they don’t perform a blind transfer and instead ask the other person about this option. The other person was able to add the option to the account without needing to speak to me. 5 minutes later I could connect using the new APN and was getting 123.209.12.nnn IP address (however interestingly enough, I was still seeing a /8 subnet on it and 10.64.64.64 as the default gateway)