How do I set an empty search domain on Airport/Time Capsule My ISP supplies their own search domain via DHCP, which I don't want being passed on to my own devices. However, if you leave the field for 'search domain' empty on an Airpot/Time Capsule it will revert to the ISP default once the text box loses focus. Is it possible to override the value to empty?
On the AirPort or TimeCapsule that is acting as DHCP and/or NAT, placing a period “.” in the Domain Name field will push a null domain name search to its DHCP clients…  

It does this by making yer DHCP clients’ treat hostnames as fully qualified…  That will not disable domain name searches on the DHCP clients if they are configured to use search domains…  

BUT, it will eliminate having yer ISP’s domain name appended as an additional domain name search…  With the added benefit of slightly faster DNS resolutions eliminating parent and child domain searches…