IP change and IP redirection

["Liam Ward" <liam@dv4.com>]

Hi all,

One of our servers is co-located at an ISP. The ISP would like us to 
change its IP address. They are going to set up IP redirection to 
help in the transition. If someone has experience of this, I would 
appreciate the benefit of that experience. By the way, the server is 
a registered name server.

According to the ISP, the IP redirection is completely transparent. 
All I need to do for now is change my /etc/network/interfaces (and 
/etc/hosts and /etc/resolv.conf) and reboot. I don't need to have 
eth0 configured for both the old and new IP addresses and services 
that are bound to the old IP address function normally. This sounds a 
bit fishy to me.

My feeling is that I should change every IP-related configuration on 
the machine to the new address when changing the eth0 configuration. 
This is not a big problem except for the DNS changes which will take 
time to propagate. I've set the TTLs to a small value in the zones 
for which this server is authoritative.

Can anyone confirm my thoughts above and suggest the best order in 
which to do the DNS changes (including the IP address change of the 
name server with the registrar).

Thanks,

Liam