Best way to make a machine boot with or without a Internet connection

[Aryeh Friedman]

Due to storm related damage my ISP went out for a few (12) hours earlier in
the week and while I got it usable without a Internet connection by putting
everything in my LAN in /etc/hosts (I also run a local_unbound --> local
bind9 on my file server which I have created a zone file for the LAN
machines also), but it was very slow in booting due to ntpdate, tomcat and
sendmail not being to connect to the Internet for either forward or reverse
DNS.   I don't want to turn these services off, but I want to be able to do
a normal boot (no long hangs) if the ISP goes down again.   What is the
best way to do this?

-- 
Aryeh M. Friedman, Lead Developer, http://www.PetiteCloud.org