Changing your O2 IP
Dynamic/fixed - what's the issue?
O2 offer fixed and dynamic IPs with most customers taking dynamic as fixed carries an additional cost of £5 per month.
However, there is one very interesting quirk with O2's dynamic IPs, they're not very dynamic at all -in fact you're likely to find that you have the same IP for months on end. This is because O2 ties your assigned IP to the router MAC address.
So, this allows you to force a change of dynamic IP.
How do you do that?
Well that depends on which router you are using.
If you're using the O2 Wireless Box then it is a little involved and requires you to telnet into the router and issue a short series of commands. A very useful guide on how to do this can be found here - thanks Oliver341
The process is fairly simple and Oliver341 has helpfully added a utility to the page to generate random MAC addresses. This goes some way towards reducing the risk of using a MAC address that is in use by another customer. Even better would be if you owned another router and then you could enter that MAC address rather than the random one.
Of course, if you have another router then there's a chance you'll be using it rather than the O2 Box. If so, have a look through its admin pages and there's a possibility that it will allow you to enter a new MAC address via the GUI - Netgears for example generally allow this (not all models though).
Is that it?
Yes, that's it. If you've successfully entered a new MAC address then this should have prompted O2's system to assign you a new IP.
However, there is one issue: O2 seems to allow two MAC addresses to be used without problem by the customer. Use three (or more) i.e. you connect using a third MAC address, and the O2 system will need to update itself. This can mean a delay in assigning a new IP of up to 40 minutes. So, if you've done this but don't seem to have internet access, don't panic. Leave it for a while and all should be well.