changing ISP

[Stef]

I have my own DNS. My ISP is changing his subnet, so my machine and
the virtual hosts on it will get a new IP adress. Can I just have two
IP addresses TTL long before the change will take place and keep them
TTL long after the change? So I have records like:

my.host.               IN A  100.100.100.100
                       IN A  200.200.200.200

where 100.100.100.100 is the old IP and 200.200.200.200 the new
one. Will web browers, mail servers, ftp clients etc. always try both
IP numbers when they try to connect, or will they give up if the first
one is not working?

Is there another way this should be done?

Cheers
Stef
-- 
WebMaster D-WERK
President SOS-ETH 
ETH Zurich
stef at hoes.li        http://hoes.li