UMA is also known as 3GPP GAN – and is used to provide a an internet based access point for mobile communications over the internet – in for example, areas where signal is weak, but there is a good wireless internet connection, this internet connection can be utilised to provide good quality voice calls over the data network.
Given that there is a distinct lack of documentation on appropriate firewall configuration for UMA on the net, I thought I’d document the ports and protocols required to get this working.
IP Protocol 50 (ESP)
IP Protocol 51 (AH)
In the UK this traffic needs to be permitted to the Orange network (no other carriers support this service yet) 18.104.22.168/20 (thanks Andy for this!)