Mysql Replication - How it works offline? i have a mysql server on a local machine but the connection is not got for users outside the local network. I want that database to be available on another server wich can handle way more requests and is more stable than the local server.
My question is:
   What is the best way to replicate the data from the local server into the web server?
   I've readed a little about slave servers, are they made for this case?
   If i use a mysql slave server and the internet on the main server goes offline, what happens to the slave?
   If the main server makes some database changes while offline will these changes be written on the slave when the master goes online again?
   Are there any performace loss for using a slave server?

I do not want a backup server, i want a server to redirect ouside queries into it, so the main server wont be affected for huge traffic and etc.
Replication sounds like what you need, as long as the slave server you envision will be used as read-only.

Connecting a slave (replica) server to a master imposes very little load on the master.  If the connection between the two is severed for whatever reason, the slave will continue to answer queries, and normally will reconnect to the master as soon as practical and pick up exactly where it left off.  Certain disruptions can cause you to have to take steps to get replication going again, but ordinarily this is automatically done.

Using a replica this way is common.  

I produce several hundred scheduled reports every day, many of which evaluate many millions of rows... and the reports are run against slave servers, to relieve the master of this additional workload.  In some cases, the slave is many thousands of miles away from the master, so, naturally, the connections are periodically lost... but they restart themselves.