Forcing an IP Address

In the “real” world you simply add an entry to /etc/hosts like

1.2.3.4 myhost

The Mac OS X world is different. For version 10.5 and later you do the following

# Create the mapping
sudo dscl localhost -create /Local/Default/Hosts/x.y.z IPAddress 127.0.0.1
# flush the cache
sudo dscacheutil -flushcache

# Show the mappings
sudo dscl localhost -readall /Local/Default/Hosts

# Delete a mapping
sudo dscl localhost -delete /Local/Default/Hosts/x.y.z
sudo dscacheutil -flushcache