Accessing Whois info after changing IP

The problem: you changed IP/nameservers for a site and after DNS changes propagated, you found out you need some information from the old site.

If you are lucky (and quick) enough, you can work around this problem by visiting whois.domaintools.com and searching for the site you want. Look for the IP Address (eg A.B.C.D), make sure it's not the same as the new site and put it in your /etc/hosts file like this:

# the format is <IP> <host>
A.B.C.D  my.site

Now you can visit the old site (eg my.site) from your browser, if it's still available from the old host.