Here is some more information about Vodafone's latest APN list. As most of you will know, APNs can be changed in your device settings/profiles to adjust your connection characteristics. Here is the current APN list:

APN: vodafone 
IP: public
Optmisation: when connection initiated in GPRS coverage
Security: Inbound initiated traffic restricted

APN: direct.vodafone.net.nz
IP: private
Optimisation: Yes, only http traffic
Security: Inbound initiated traffic allowed

APN: opt.vodafone.net.nz
IP: private
Optimisation: Yes
Security: Inbound initiated traffic restricted

MMS settings
Username : 
Password:
WAP Gateway(URL): 172.30.38.3
WAP gateway Port : 8080
MMSC(URL): http://pxt.vodafone.net.nz/pxtsend
MMSC Port: 80

vodafone This is the default APN used to access the Internet from the Vodafone network.  It now assigns public IP addresses (previously private NAT addressing).  It will provide users with an optimised experience when the connection is created in GPRS coverage areas. Sessions initiated in 3G / HSDPA coverage will bypass the optimisers.  The security policy used by this APN restricts inbound initiated traffic  – reducing the threat of unsolicited traffic from the internet. 

direct.vodafone.net.nz uses private addresses, as a consequence it uses NAT, so be aware that this will break some applications. It also bypasses the optimisers for all radio access types. 

opt.vodafone.net.nz This APN has been created to provide a fully optimised experience across all network types.  It assigns private NAT’d IP addresses and employs the same security policy as the ‘www’ APN.

You might wonder if you can get a static IP on your mobile connection. The answer is that the public range addresses that Vodafone use are issued by IANA on the basis that they are only to be used for dynamically issued mobile connections. They apparently don't have any available addresses that could be issued staticly, and there would be undesirable complications in doing so anyway. Don't complain too bitterly, it is not that long since all public APNs used private addresses and NAT, which broke more applications.