DNS Tricks

 In order to test sometimes you need to create a fake local DNS. This is so that only your computer can visit a new site before it becomes public.

If your computer is managed by UCSF you may have trouble following these directions as Symantec Endpoint Protection will prevent you from editing your host file.   You may need to submit a DNS request for your development environment in this case.  

Alter local host file and test local environment

For window users that will be something like:


on linux and macs:


add the new entry     emergency.ucsf.edu

Flushing DNS

Go to a command prompt on a PC or terminal window on Linux/Mac

On Windows

ipconfig /renew 


ipconfig /flushdns

On linux:

/etc/rc.d/init.d/nscd restart

On mac

dscacheutil -flushcache

Testing DNS update

Very simple just "ping" your new host

ping emergency.ucsf.edu