Hi,
The vodafone bit is a guess but....

I use opendns for internet filtering for my machines at home.
My router is setup to use the opendns addresses (208.67.222.222 and 208.67.220.220) and all my machines use my router address for resolving.

My opendns network matches my external ip address (which concurs with myipaddress.org). That address is setup in opendns to filter pornographic sites - and my opendns settings are set for dynamic addresses.

I use ddclient on one of my (linux) machines to update the network at opendns.

Everything looks fine - but opendns doesn't see any data coming from my network.

I recently switched to vodafone broadband at home - and I have a feeling it's since I did this that it's stopped working).

I test it by going to a blocked site (e.g. playboy.com) and it's getting there.

Does anyone have any experience with this?
 
Cheers,
Ian