mod_rewrite based on ip
.htaccess, apache, mod-rewrite
Solution
You can use the REMOTE_ADDR variable in a RewriteCond
RewriteCond %{REMOTE_ADDR} !^10\.0\.1\.1$
RewriteRule ^ /maintenance.html
Just change the condition to match the IPs you want, for more than one you can use ^(ip1|ip2|...|ipn)$.
About how to disable the maintenance mode without changing the .htaccess file I think that's not possible short of writing a program that would delete it or otherwise modify it, an easy one would be to rename it.
Problem
I'd like to implement mod_rewrite to put my site into maintenance. Basically all IP addresses except a handful we specify would be forwarded to a static html page. Please can someone help with this rule. Also is there a way to turn this on and off easily without editing the htaccess file?